依旧强大:互联网的隐藏秩序
瑞士信贷第一波士顿公司
CREDIT SUISSE FIRST BOSTON CORPORATION
Americas
Americas
迈克尔·莫布森 1 212 325 3108 [email protected]
Michael J. Mauboussin 1 212 325 3108 [email protected]
亚历山大·谢伊(Alexander Schay) 1 212 325 4466 [email protected] 股票研究
Alexander Schay 1 212 325 4466 [email protected] Equity Research
美国投资策略 2000 年 7 月 7 日
U.S. Investment Strategy July 7, 2000
Still Powerful
Still Powerful
互联网的隐形秩序
The Internet’s Hidden Order
• 尽管互联网板块在过去六个月里经历了回调,在线公司的排名与市值之间的关系,仍然呈现出幂律分布的行为特征。
• Despite a correction in the Internet sector over the past six months, the relationship between rank and market value of online firms continues to exhibit power law behavior.
• 这种赢家通吃的市值分布格局,支持了这样一个观点:网络世界的竞争具有一些独特特征。例如,大公司可以像小公司一样快速增长,而这一媒介的正向强化特性,为领先者提供了竞争优势的来源。
• This winner-take-all, market-capitalization distribution supports the notion that competition on the Web has some unique characteristics. For example, large firms can grow as quickly as small firms and the positive reinforcing nature of the medium provides leaders with a source of competitive advantage.
我们会继续专注于那些拥有客户的公司,
• We would continue to focus on the companies with customers,
资本,以及长期可行的商业模式。
capital, and viable long-term business models.
Executive Summary
Executive Summary
尽管互联网表面上错综复杂,但其中潜藏着内在秩序。研究显示,网页在不同站点之间的分布遵循一种普适的幂律分布。幂律是描述可测量数量——例如特定强度地震的发生次数,或某一人口规模区间内城市数量——的分布函数。网页数量遵循着一种异常稳定的规律性。粗略来说,幂律揭示了一个事实:大量站点只拥有少量网页,而极少数站点则拥有海量网页。
Despite the Internet’s apparent complexity, hidden order exists. Studies demonstrate that Web pages are distributed among sites according to a universal power law. Power laws are distribution functions for measurable quantities—such as the number of earthquakes that occur at a particular intensity, or the number of cities that exist within a given range of population. The number of Web pages adheres to a remarkably stable regularity. Roughly described, power laws hold 1 that many sites have few pages and that few sites have many pages.
网页的分布并非唯一服从幂律定律的在线现象。每个网站的访客分布同样遵循幂律:许多网站只有极少数用户,而少数网站拥有极大量用户。尽管这两条规律看似直观,其精确性质却蕴含着深远影响。依赖吸引用户并从中盈利的在线企业面临重大挑战。观察到的幂律表明,新成立的网站吸引大量用户的概率很低。事实上,从 1999 年 1 月到 2000 年 4 月,MediaMetrix“前三强(Top 3 Properties)”榜单中排名前 25 的公司有 20 家仍留在前 25 名。
The distribution of Web pages is not the only online phenomenon that adheres to a power law. The distribution of visitors per site follows a power law as well: many sites have very few users, and a few sites have very many users. Although intuitive, the precise nature of these two regularities carries profound implications. Online firms that depend on the ability to attract and monetize users face significant challenges. The observed power laws suggest a low probability that 2 newly established sites will attract a significant number of users. In fact, from January 1999 to April 2000, 20 of the top 25 companies in the MediaMetrix “Top 3 Properties” remained in the top 25.
4 我们于 1999 年底首次探讨了幂律法则与互联网的关系。尽管过去六个月互联网股票价格经历了大幅回调,但排名与线上公司市值之间的关系依然最能通过幂律法则来表达。这种赢家通吃的分布格局,持续支持着这样一种观点——网络世界的竞争具有独特特征。大型企业不仅能像小型企业一样快速成长,而且该媒介的“正向强化”特性也转化为可持续竞争优势的来源。本报告将探讨可能促成上述分布格局的若干因素。
4 We first explored power laws and the Internet in late 1999. Despite a sharp correction in Internet stock prices over the last six months, the relationship between rank and the market value of online firms is still best expressed with a power law. This winner-take-all distribution continues to support the notion that competition on the Web has unique characteristics. Not only can large firms grow as quickly as small firms, but the positive-reinforcing nature of the medium also translates into a source of sustainable competitive advantage. This report explores some of the factors that may contribute to the observed distribution.
Powerful Web
Powerful Web
不容置疑——网络上的活动高度集中。为了展示网站受欢迎程度的具体分布,我们使用 MediaMetrix 2000 年 4 月前 500 个域名的数据,将独立网站用户数放在横轴,页面浏览量放在纵轴。结果在双对数坐标图上呈现出一条直线。数据显示,前 5%(即 25 个站点)贡献了总流量的 31%。这与更广泛的网络研究结果一致——头部网站占据了总流量的极大份额。也就是说,仅占总网站数 0.1%(即前 119 个站点)就占据了站点总访问量的 32%。真正能做大做强的网站凤毛麟角,能获得大量用户流量的网站也寥寥无几。
Let there be no mistake—activity on the Web is highly concentrated. To show the breakdown of Web site popularity, we ranked the number of unique site users on the horizontal axis and plotted page views on the vertical axis, using MediaMetrix data for the top 500 domains in April 2000. The result is a straight line when using a double logarithmic scale. The data show that the top 5%, or 25 sites, account 5 for 31% of the total volume of traffic. This is consistent with broader studies of the Web showing that the top sites account for a very large percentage of total traffic volume. That is, one-tenth of one percent of the total, or the top 119 sites, 6 account for 32% of the total volume of site traffic. Very few Web sites get large, and very few Web sites get a lot of user traffic.
图 1 幂律分布
Figure 1 Power Laws
T o p 5 0 0 , Ap r il 2 0 0 0 10 5
T o p 5 0 0 , Ap r il 2 0 0 0 10 5
Hits (000)
Hits (000)
10 4
10 4
10 3
10 3
10 2 10 0 10 1 10 2 R an k
10 2 10 0 10 1 10 2 R an k
来源:MediaMetrix 与瑞信第一波士顿分析。
Source: MediaMetrix and CSFB analysis.
根据排名与频率绘制的对数曲线若呈斜率接近 1 的直线(如图 1 所示),即体现齐普夫定律。这种规律性已在多个领域被观察到,包括地震震级与频率、城市规模排名、以及语言中词语的分布。当齐普夫分布以线性尺度绘制时,极端情况便一目了然:少数元素得分极高,中等数量元素得分居中,而大量元素得分极低(分布的长尾紧贴横轴)。
A logarithmic plot of rank versus frequency that is a straight line with slope near unity (as seen in Figure 1) illustrates Zipf’s law. This regularity has been observed in diverse realms, including the magnitude and frequency of earthquakes, rank and city sizes, and the distribution of words in a language. Extremities are apparent when Zipf distributions are plotted on a linear scale. A few elements score very high, a medium number of elements score in the middle of the road, and an enormous number of elements score very low. (The long tail of the distribution hugs the x-axis.)
幂律分布并不常见——它们代表的是特殊情况。高斯分布(正态分布)在自然界中比幂律分布常见得多。例如,房间内气体分子的速率、新生儿的体长、以及整个股票市场中市值的分布,都遵循高斯分布。高斯系统的一个共同特征是独立性。以气体分子为例,任何一个分子的速率都不会明确地取决于其他分子的速率。即便分子之间发生碰撞,相互影响的程度也很小。
Power laws are unusual—they represent special situations. Gaussian, or normal, distributions are much more common in nature than power law distributions. For example, the velocity of gas molecules in a room, the length of new-born babies, and the distribution of market capitalizations for the broader stock market all follow Gaussian distributions. One common trait of Gaussian systems is independence. To use gas molecules as an illustration, the velocity of any given molecule will not explicitly depend on the velocity of the other molecules. Even when the molecules collide, there is only a small degree of interaction.
相反,幂律分布出现在高度互动的情境之下。最典型的例子是森林火灾:一片森林中某棵树着火
In contrast, power laws occur when there is a high degree of interaction. The canonical example is a forest fire. The probability that a given tree in the forest
一棵树是否会被烧毁,很大程度上取决于森林中其他树木是否在燃烧,以及这棵树相对于其邻居的位置。树木底层“网络”位置决定了火灾是会熄灭、被限制在小范围内,还是演变成一场大火。这种复杂性导致森林火灾的规模呈现出幂律分布。网站流量的集中化也转化为市场价值的集中化,因此最常被使用的网站通常拥有最好的机会来构建可行的商业模式。有趣的是,尽管过去六个月该行业显著下滑,但互联网公司的估值仍然符合幂律分布。这一点可以从图 2 中看出。
will burn is highly dependent on whether other trees in the forest are burning and the location of the tree relative to its neighbors. The underlying “network” position of the trees determines whether or not the blaze dies out, is confined to a small area, or becomes a conflagration. This complexity gives rise to power law distributions in the sizes of forest fires. The concentration of hits on a Web site also translates into a concentration of market value, so the most frequently used sites generally have the best opportunity to create viable business models. It’s interesting that the valuation of Internet companies still conforms to a power law, despite a pronounced downturn in the segment over the last six months. This can be seen in Figure 2.
图二 互联网市值幂律分布
Figure 2 Internet Market Capitalization Power Law
Internet 10 6
Internet 10 6
Market Value (000,000)
Market Value (000,000)
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
10 5 10 4 10 3 10 2 10 1 10 0 10 0 10 1 10 2 Rank
10 5 10 4 10 3 10 2 10 1 10 0 10 0 10 1 10 2 Rank
资料来源:瑞信第一波士顿银行(CSFB)分析。
Source: CSFB analysis.
这一分析提供了有力证据,表明市场在相对估值层面仍在正确地为互联网公司定价。需要指出的是,这些数据对绝对估值问题仍然保持沉默。与普遍认知相反,互联网估值确实存在某种可识别的秩序。那么问题就变成了:这种秩序是否为互联网股票独有?其他行业是否也表现出同样的特征——即绝大部分市值集中在少数几家公司手中?我们分析了来自 18 个不同行业分类的 46 个板块,试图回答这个问题。这项广泛调查显示,有 9 个板块呈现出显著的幂律特征,详见附录。
This analysis provides compelling evidence that the market continues to value Internet companies correctly on a relative basis. It is important to note that these data remain mute on the issue of absolute valuations. Contrary to popular perception, there is some discernible order to Internet valuations. So the question becomes, Is this order unique to Internet stocks? Do other industries exhibit the same characteristics, where a disproportionate share of the total market capitalization resides in a handful of firms? We analyzed 46 sectors from 18 different industry classifications in an attempt to answer this question. This broad survey revealed that 9 sectors exhibited strong power law characteristics. They are displayed in the Appendix.
强者恒强
The Strong Get Stronger
虽然没有纯粹的互联网品牌能够受益于线下实体存在的强化,但在线媒介的许多独特特性,使得那些已经领先的公司能够继续保持领先。《绝对权力》中提到的一个例子是,新网站倾向于链接那些已经受欢迎的网站,以获取更多流量。这种增强的链接结构在后来的多项网络研究中都得到了再次确认。
While no pure Internet brand is reinforced by the benefit of a physical presence, many particular characteristics of the online medium allow those companies that are already ahead to stay ahead. One example noted in “Absolute Power” is that new sites tend to link to already-popular sites in a bid for increased traffic. Such a reinforcing link structure is reconfirmed in a number of subsequent studies of the Web.
对万维网进行的迄今为止最全面的研究,揭示了其宏观结构的一些有趣发现。IBM 位于加利福尼亚州圣何塞的阿尔马登研究中心的研究人员,对超过 2 亿个页面和 15 亿个链接(约占当前万维网估计总量的五分之一)进行了分析。他们发现,万维网的连接结构酷似一个领结。领结的左侧是他们所称的“新手”。这一站点群体由 4300 万个页面(占总数的 21%)组成,这些页面相对较新。这些站点链接到中央区域,即所谓的“强连通分量”(SCC)。然而,中央区域的那些成熟参与者——拥有超过 5600 万个页面——并不会反向链接回这些新手。SCC 中的站点包括门户网站,以及 MediaMetrix 数据中许多顶尖的企业站点。领结的右侧则是“内向者”。这一群体包含大量知名度较低的电子商务站点。尽管 SCC 链接到了这些内向者,但内向者却不会提供指向强连通中心的链接。
The most comprehensive study of the Web to date reveals some interesting insights into its macroscopic structure. Researchers at IBM’s Almaden Research Center in San Jose, California, examined over 200 million pages and 1.5 billion links (roughly one-fifth of the estimated current Web). They found that the Web’s connectivity resembles a bow tie. On the left side of the tie is what they dub the “newbies.” This group of sites consists of 43 million pages (or 21% of the total) that are relatively new. These sites link to the center, or what is called the “Strongly Connected Component” (SCC). However, these established players in the center—with over 56 million pages—do not link back to the newbies. Sites in the SCC consist of portals and many of the top corporate sites in the MediaMetrix data. On the right side of the bow are the “introverts.” This group includes a lot of lesser-known e-commerce sites. Although the SCC is linked to these introverts, 7 the introverts do not provide links back to the strongly connected center.
大多数搜索引擎依赖所谓的“爬虫”(crawlers)。爬虫的工作方式是:先给一个网页建立索引,然后跳转到这个网页所链接的其他页面,再给那些页面建立索引,如此不断重复。
Most search engines rely on so-called “crawlers.” Crawlers work by indexing a Web page, jumping to other pages linked to it, then indexing those, and so on.
阿尔马登的研究推翻了早先的一种观点,即任意两个网页之间只需通过相对较少的超链接就能相连。为了在未来获得更广泛的覆盖范围,搜索引擎将需要比现在从更多样化的起点出发进行爬取。在这之前,它们会继续将流量引导至那些最受欢迎且地位稳固的网站——而对新生网站则毫无回报。随着大多数搜索查询中只呈现出日益增长的网络的一小部分,流向现有强连通网站的流量模式得到了正向强化。
The Almaden study contradicts earlier suggestions that any two Web pages are connected by a relatively small number of hyperlinks. In order to give wide breadth of coverage in the future, search engines will have to crawl from a 8 greater diversity of starting points than they do today. Until this occurs, they will continue to channel traffic to the most popular and entrenched Web sites— without any reciprocity for the newbies. With only a fraction of the growing Web appearing in most search queries, traffic patterns to the existing strongly connected sites are positively reinforced.
广告螺旋 —— 那么,这如何转化为经济价值呢?集中价值的一个例子是广告。广告主在新媒体上不愿冒险:约 95% 的网络广告投放在仅占全部广告支持网站 1% 的站点上。尽管获得在线广告收入的网站绝对数量仍在增长,但流向排名前 50 的网站的广告支出份额却在持续上升。
Advertising Spiral So how does this translate into economic value? One example of the value concentration is advertising. Advertisers aren’t taking any chances with the “new” medium: about 95% of Web advertising is spent on 1% of all ad-supported Web sites. And while the absolute number of Web sites receiving online ad revenues continues to grow, the percentage share of ad dollars being spent at the top 50 sites continues to rise.
| 发布商 | 网络广告总收入占比 |
|---|---|
| 数据未提供 | 数据未提供 |
Table 1 Publishers’ Share of Total Web Ad Revenues
| 年份 | 1998 | 1999 | 2000 |
|---|---|---|---|
| 前十大站点 | 72% | 74% | 76% |
| 前二十五站点 | 85% | 87% | 89% |
| 前五十站点 | 92% | 95% | 95% |
1998 1999 2000 Top 10 Sites 72% 74% 76% Top 25 Sites 85% 87% 89% Top 50 Sites 92% 95% 95%
来源:eMarketer 估计。
Source: eMarketer estimates.
尽管这一格局可能随着广告主将资金从门户网站转向更具针对性的垂直网站而发生变化,但广告主仍然倾向于选择高流量网站。
Although this profile may change as advertisers shift their dollars away from portals and toward more highly targeted vertical Web sites, advertisers continue to gravitate toward high-traffic sites.
试图解释电子市场特征的网络竞争模型——在电子市场中,少数网站繁荣发展,而大多数网站被推向灭绝边缘——得出的结论是,突变会发生。随着网站之间的竞争升温,一种深刻的转变可能会出现:从众多网站同时繁荣的环境,转向赢家通吃的市场,即少数网站吸引大多数用户。这归因于网站之间的非线性相互作用,由于来自其他网站的极端竞争压力,这种相互作用有效降低了部分网站的增长速率。
Web Competition Models that try to explain the characteristics of electronic markets—where a few sites thrive while most are driven to the verge of extinction—conclude that sudden transitions occur. As the competition between Web sites heats up, a profound shift can take place from an environment where many sites simultaneously thrive to a winner-take-most market where a handful of sites attract most users. This is attributable to a nonlinear interaction among sites, which effectively reduces the growth rate of some, owing to extreme competitive 9 pressure from others.
当企业花费巨资维持增长时,不难看出它们可能达到一个关键支出点——届时资金会(随着业务基本面一同)枯竭。即便只有两个竞争网站,这一现象也可能发生,这类似于生态学中的“互斥原理”。当竞争性捕食非常激烈时,捕食同一猎物的两种捕食者无法在均衡状态下共存。
With firms spending enormous sums to sustain growth, it is easy to see that it is possible to reach a critical spending point where funding dries up (in tandem with the business fundamentals). This phenomenon can occur even with only two competing sites, and is comparable to the “principle of mutual exclusion” in ecology. Two predators of the same prey cannot coexist in equilibrium when 10 competitive predation is very strong.
一旦网站的固定开发成本投入后,为满足增长需求而扩展容量的成本相对较低。因此随着网站数量激增,关注总需求就成为当务之急。
Once the fixed development cost of operating a Web site is spent, it is relatively inexpensive to scale capacity to meet increased demand. So as Web sites proliferate, focus on aggregate demand becomes the order of the day.
遗憾的是,许多互联网公司这个“捕食者”正在争夺同一群消费者这个“猎物”的注意力与资源。
Unfortunately, many Web company “predators” are competing for the attention and resources of the same consumer “prey.”
Conclusion
Conclusion
图 3 创业资本持续流入情况
Figure 3 Trailing Venture Capital Money Flows
$35 90% $30 80% 70% $25
$35 90% $30 80% 70% $25
Dollars (billions)
Dollars (billions)
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
| 60% | % 互联网 | |
|---|---|---|
| $20 | 50% | |
| $15 | 40% | |
| 30% | ||
| $10 | ||
| 20% | ||
| $5 | 10% | |
| $ - | 0% | |
| 1995 1996 1997 1998 1999 一季度 1999 二季度 1999 三季度 1999 四季度 1999 2000 一季度 | ||
| 总金额 | 互联网金额 | 互联网占比 |
60% % Internet $20 50% $15 40% 30% $10 20% $5 10% $- 0% 1995 1996 1997 1998 Q1 99 Q2 99 Q3 99 Q4 99 1999 Q1 00 Total $ Internet $ % Internet
来源:VentureOne Corp. 及 CSFB 的分析。
Source: VentureOne Corp. and CSFB analysis.
过去两年,风险资本公司的投资规模前所未有。仅 1999 年第四季度,就有 149 亿美元投向了新商业机会。这一季度总额超过了美国风险资本历史上的任何年度金额。继 1999 年之后,新千年的第一个季度,风险资本支持的公司又筹集了 178 亿美元,其中约 84% 流向了互联网相关创业公司。我们今天仍像六个月前一样,对大多数在线公司能否在无情的幂律法则下生存存有疑虑。
Investment by venture capital firms has been unprecedented in the last two years. In the fourth quarter of 1999 alone, $14.9 billion was spent on new business opportunities. This quarterly total was higher than any annual amount in the history of U.S. venture capital. Picking up where 1999 left off, venture-backed firms raised $17.8 billion in the first quarter of the new millennium. About 84% went to Internet-related ventures. We register our skepticism today, as we did six months ago, about the ability of most online firms to survive the unforgiving rule of the power law.
自第二季度以来,市场对互联网企业的看法发生了显著变化。投资者现在正聚焦于一个新缩写:
Since the beginning of the second quarter there has been a marked change in perception of Internet businesses. Investors are now focusing on a new acronym:
P2P——通往盈利之路。随着一些知名公司股价跌至 52 周新低,另一些则干脆关门大吉,投资者必须记住当今市场领先企业固有的优势:它们拥有客户,拥有资本,并且直接受益于网络自我强化的特性。
P2P—the path to profitability. With some high-profile firms at 52-week lows and others closing their doors altogether, investors must remember the inherent advantage of today’s market leaders. They have the customers. They have the capital. And they benefit directly from the self-reinforcing nature of the Web.
注瑞士信贷第一波士顿公司可能在过去三年内曾担任上述任何一家或全部公司的证券公开发行的主承销商或联席承销商,或为其证券做市。
N.B.CREDIT SUISSE FIRST BOSTON CORPORATION may have, within the last three years, served as a manager or co-manager of a public offering of securities for or makes a primary market in issues of any or all of the companies mentioned.
1 该发现最初发表于《万维网的增长动力学》一文中。
1 This was initially reported in “Growth Dynamics of the World-Wide Web.”
胡伯曼(Huberman, B.A.)与阿达米克(Adamic, L.)1999 年 9 月 9 日发表于《自然》杂志第 401 卷。此后,该结果在布罗德(Broder, Andrei)等人的《网络中的图结构》一文中再次得到验证。
Huberman, B.A., Adamic, L. Nature Vol. 401, September 9, 1999. Since then the results have been reconfirmed in “Graph Structure in the Web.” Broder, Andrei,
et. al. IBM 阿尔马登研究中心,加利福尼亚州圣何塞,2000 年 6 月。2 同上,Huberman。值得注意的是,所观察到的幂律行为源自所有网站的使用日志,而不仅仅是商业网站的使用日志。公司战略会影响打破现有格局的能力。3 有六家公司的属性被竞争对手吸纳,这些竞争对手在 4 月份仍位列前 25 名。其余公司仍保持在 100 名以内。
et. al. IBM Almaden Research Center, San Jose, CA., June 2000. 2 ibid. Huberman. It’s important to note that the observed power law behavior was derived from usage logs for all web sites, not usage logs for commercial web sites alone. Corporate strategy can influence the ability to crack the line-up. 3 Six properties were absorbed by competitors that remained in the top 25 in April. The balance of the firms remained in the top 100.
迈克尔·莫布森、亚历山大·谢伊、斯蒂芬·卡瓦贾,《绝对权力》,
4 Michael Mauboussin, Alexander Schay, Stephen Kawaja, “Absolute Power,”
瑞士信贷第一波士顿股票研究,1999 年 12 月 21 日。
Credit Suisse First Boston Equity Research, December 21, 1999.
尽管我们无法在网站流量与市值之间找到直接的统计相关性,但网站访问量排名前 25 的公司中,有 14 家同时也位列市值前 25 名。
5 Although we could find no direct statistical correlation between site traffic and market capitalization, 14 of the top 25 companies in site volume were also in the top 25 in terms of market value.
6 “万维网的增长动力。”Huberman, B.A.,Adamic, L.,《自然》杂志第 401 卷,1999 年 9 月 9 日。
6 “Growth Dynamics of the World-Wide Web.” Huberman, B.A., Adamic, L. Nature Vol. 401, September 9, 1999.
7 《网络中的图结构》,安德烈·布罗德等,IBM 阿尔马登研究中心,加州圣何塞,2000 年 6 月。
7 “Graph Structure in the Web.” Broder, Andrei, et. al. IBM Almaden Research Center, San Jose, CA., June 2000.
8 “强化版搜索引擎”。《自然》期刊第 405 卷,2000 年 5 月 11 日,www.nature.com 9 “网站的竞争动态”。毛雷尔·塞巴斯蒂安·M、休伯曼·贝尔纳多·A。施乐帕洛阿尔托研究中心,2000 年 3 月 17 日。
8 “Souped Up Search Engines.” Nature Vol. 405, May 11, 2000 www.nature.com 9 “Competitive Dynamics of Web Sites.” Maurer, Sebastian M., Huberman, Bernardo A. Xerox Palo Alto Research, March 17, 2000.
10 Ibid.
10 Ibid.
Appendix
Appendix
在对 18 个不同行业的 46 个板块进行幂律趋势分析后,我们使用 FactSet 行业分类数据。这项广泛的调查表明,其中有 9 个行业呈现出明显的幂律特征。(见表 2。)在所研究的每个行业中,我们发现规模最大的公司最能符合幂律分布。
Complements We analyzed 46 sectors from 18 different industries for possible power law trends. Data are from FactSet industry classifications. This broad survey shows that 9 of these industries show strong power law characteristics. (See Table 2.) In every industry studied we found that the largest companies best follow a power
法律。第一列展示了这类公司的相对规模。第二列衡量了每个行业被龙头公司主导的程度,第三列则量化了这些公司对幂律分布的拟合优度(数值越接近零,拟合度越好)。此处我们采用标准统计方法,将均方残差的平方根作为拟合优度检验指标。
law. We show the relative size of this subset of companies in the first column. The second column gives a measure of the extent to which each industry is dominated by its largest companies, and the third column quantifies how well the companies fit a power law. (Smaller numbers closer to zero correspond to better fits.) Here we employ the standard statistical practice of taking the square root of the mean squared residual as a goodness of fit test.
表 2 幂律分布行业 遵循幂律分布的比例 前 5% 公司所持市场份额 幂律拟合残差均方根 互联网 47% 64% 0.152 生物科技 46% 64% 0.094 储蓄与贷款 45% 66% 0.091 电信设备 39% 86% 0.209 特种化学品 35% 40% 0.121 半导体 28% 64% 0.137 餐饮 19% 85% 0.214 软件 17% 85% 0.126 服装 16% 67% 0.127
Table 2 Power Law Sectors Portion Following Market Share Held By RMS of Residuals in Industry Power Law Companies in Top 5% Power Law Fit Internet 47% 64% 0.152 Biotech 46% 64% 0.094 Savings & Loan 45% 66% 0.091 Telecom Equipment 39% 86% 0.209 Specialty Chemicals 35% 40% 0.121 Semiconductors 28% 64% 0.137 Restaurants 19% 85% 0.214 Software 17% 85% 0.126 Apparel 16% 67% 0.127
来源:CSFB 分析。
Source: CSFB analysis.
为了进一步说明表 2 所使用的统计方法,我们以互联网行业为例进行更详细的展示。
To further illustrate the procedure used to establish the results in Table 2, we present the Internet industry results in greater detail.
图 4:互联网服务行业
Figure 4 Internet Services Industry
互联网产业 108
In te r n e t In d u s tr y 10 8
Market Value (000)
Market Value (000)
10 4
10 4
10 0
10 0
1 0 -4 10 0 10 1 10 2 R ank
1 0 -4 10 0 10 1 10 2 R ank
资料来源:CSFB 分析。
Source: CSFB analysis.
图 4 展示了互联网行业 297 家公司中每一家的市值(单位:千美元)。按排名来看,前 140 家公司(占 47%)紧密贴合拟合线。图 4 说明了拟合线是如何选定的。每个数据点都是对行业整体中某一部分进行幂律拟合的结果。当拟合中包含超过 140 家公司时,均方根误差值开始系统性增大,这表明偏离了幂律行为。
Figure 4 displays the market value (in thousands) of each of the 297 companies in the Internet industry. As a function of rank, the top 140 companies (47%) closely follow the fit line. Figure 4 demonstrates how the fit line was chosen. Each point is the result of a power law fit to a portion of the total industry. When more than 140 companies are included in the fit, the RMS values begin to systematically increase, which indicates divergence from power law behavior.
因此,图 5 中的拟合线被选定为与排名前 140 的公司最为匹配。
Therefore the fit line in Figure 5 is chosen to best fit the top 140 companies.
图 5 互联网服务行业
Figure 5 Internet Services Industry
最适配点位于(140, 0.152)
Best Fit at (140, 0.152)
0.4
0.4
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
残差均方根 0.3 0.2 0.1 0.0 0 50 100 150 200 250 测试点数
RMS of Residuals 0.3 0.2 0.1 0.0 0 50 100 150 200 250 Points in Test
数据来源:瑞士信贷第一波士顿银行(CSFB)分析。
Source: CSFB analysis.
– 10 –
– 10 –
图 6 幂律区间
Figure 6 Power Law Segments
Internet 0.4 10 8
Internet 0.4 10 8
Market Value (000,000)
Market Value (000,000)
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
| 残差的 RMS |
|---|
| 0.3 |
| 10 4 |
| 0.2 |
| 10 0 |
| 0.1 |
| 10 -4 0.0 |
| 10 0 10 1 10 2 0 50 100 150 200 250 |
RMS of Residuals 0.3 10 4 0.2 10 0 0.1 10 -4 0.0 10 0 10 1 10 2 0 50 100 150 200 250
Rank Points in Test
Rank Points in Test
Biological Technology 6 1.0 10
Biological Technology 6 1.0 10
Market Value (000,000)
Market Value (000,000)
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
| 残差均方根 |
| 0.8 |
| 10 3 |
| 0.6 |
| 0.4 |
| 10 0 |
| 0.2 |
| 10 -3 0.0 |
| 10 0 10 1 10 2 0 100 200 300 |
RMS of Residuals 0.8 10 3 0.6 0.4 10 0 0.2 10 -3 0.0 10 0 10 1 10 2 0 100 200 300
Rank Points in Test
Rank Points in Test
储蓄与贷款 10 5 0.25
Savings and Loans 10 5 0.25
Market Value (000,000)
Market Value (000,000)
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
| 残差之均方根 |
|---|
| 10⁴ 0.20 |
| 10³ 0.15 |
| 10² 0.10 |
| 10¹ 0.05 |
| 0 |
| 10⁰ 0.00 |
| 10⁰ 10¹ 10² 0 100 200 300 |
RMS of Residuals 10 4 0.20 10 3 0.15 10 2 0.10 10 1 0.05 0 10 0.00 10 0 10 1 10 2 0 100 200 300
排名 测试得分
Rank Points in Test
来源:CSFB 分析。
Source: CSFB analysis.
– 11 –
– 11 –
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
图 7 幂律分布领域 电信设备 10 8 0.5 (百万美元) 残差 0.4 10 4 0.3 市场 0.2 价值 10 0 RMS 0.1 10 -4 0.0 10 0 10 1 10 2 0 排名 特种化学品 10 6 1.0 (百万美元) 残差 0.8 10 3 0.6 市场 0.4 价值 10 0 RMS 0.2 10 -3 0.0 10 0 10 1 10 2 0 排名 半导体 10 6 1.0 (百万美元) 残差 10 5 0.8 10 4 0.6 市场 10 3 价值 0.4 10 2 RMS 0.2 10 1 10 0 0.0 10 0 10 1 10 2 0 排名
Figure 7 Power Law Segments Telecommunication Equipment 10 8 0.5 (000,000) Residuals 0.4 10 4 0.3 Value of 0.2 Market 10 0 RMS 0.1 10 -4 0.0 10 0 10 1 10 2 0 Rank Specialty Chemicals 10 6 1.0 (000,000) Residuals 0.8 10 3 0.6 Value of 0.4 Market 10 0 RMS 0.2 10 -3 0.0 10 0 10 1 10 2 0 Rank Semiconductors 10 6 1.0 (000,000) Residuals 10 5 0.8 10 4 0.6 Value 10 3 of 0.4 10 2 RMS Market 0.2 10 1 10 0 0.0 10 0 10 1 10 2 0 Rank
资料来源:CSFB 分析。
Source: CSFB analysis.
| 测试得分 | 50 | 100 | 150 | |
|---|---|---|---|---|
| 测试得分 | 25 | 50 | 75 | 100 |
| 测试得分 | 25 | 50 | 75 | 100 |
– 12 –
50 100 150 Points in Test 25 50 75 100 Points in Test 25 50 75 100 Points in Test – 12 –
图 8 幂律分布区间 餐厅 10 6 0.6 (百万) 残差 10 3 0.4 市场 10 0 RMS 0.2 价值 10 -3 0.0 10 0 10 1 10 2 0 25 排名 软件 10 8 0.4 (百万) 残差 0.3 10 4 市场 0.2 价值 10 0 RMS 0.1 10 -4 0.0 10 0 10 1 10 2 0 排名 服装 10 6 0.4 (百万) 残差 0.3 10 3 市场 0.2 价值
Figure 8 Power Law Segments Restaurants 10 6 0.6 (000,000) Residuals 10 3 0.4 Value of 10 0 RMS 0.2 Market 10 -3 0.0 10 0 10 1 10 2 0 25 Rank Software 10 8 0.4 (000,000) Residuals 0.3 10 4 Value 0.2 of Market 10 0 RMS 0.1 10 -4 0.0 10 0 10 1 10 2 0 Rank Apparel 10 6 0.4 (000,000) Residuals 0.3 10 3 Value 0.2 of
0 RMS
0 RMS
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
Market 10 0.1 10 -3 0.0 10 0 10 1 10 2 0 10 Rank
Market 10 0.1 10 -3 0.0 10 0 10 1 10 2 0 10 Rank
来源:CSFB 分析。
Source: CSFB analysis.
| 测试得分 |
|---|
| 50 |
| 75 |
| 100 |
| 125 |
| 150 |
| 测试得分 |
| 100 |
| 200 |
| 300 |
| 测试得分 |
| 20 |
| 30 |
| 40 |
| 50 |
| 60 |
| 70 |
– 13 –
50 75 100 125 150 Points in Test 100 200 300 Points in Test 20 30 40 50 60 70 Points in Test – 13 –
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
| 城市 | 电话号码 | 城市 | 电话号码 | 城市 | 电话号码 |
|---|---|---|---|---|---|
| 阿姆斯特丹 | 31 20 5754 890 | 伦敦 | 44 20 7888 8888 | 旧金山 | 1 415 836 7600 |
| 亚特兰大 | 1 404 656 9500 | 马德里 | 34 91 423 16 00 | 圣保罗 | 55 11 3841 6000 |
| 奥克兰 | 64 9 302 5500 | 墨尔本 | 61 3 9280 1666 | 首尔 | 82 2 3707 3700 |
| 巴尔的摩 | 1 410 223 3000 | 墨西哥城 | 52 5 283 89 00 | 上海 | 86 21 6881 8418 |
| 北京 | 86 10 6410 6611 | 米兰 | 39 02 7702 1 | 新加坡 | 65 538 6322 |
| 波士顿 | 1 617 556 5500 | 莫斯科 | 7 501 967 8200 | 悉尼 | 61 2 8205 4400 |
| 布达佩斯 | 36 1 202 2188 | 孟买 | 91 22 230 6333 | 台北 | 886 2 2715 6388 |
| 布宜诺斯艾利斯 | 54 11 4394 3100 | 纽约 | 1 212 325 2000 | 东京 | 81 3 5404 9000 |
| 芝加哥 | 1 312 750 3000 | 帕洛阿尔托 | 1 650 614 5000 | 多伦多 | 1 416 352 4500 |
| 法兰克福 | 49 69 75 38 0 | 巴黎 | 33 1 40 76 8888 | 维也纳 | 43 1 512 3023 |
| 日内瓦 | 41 22 394 70 00 | 帕萨迪纳 | 1 626 395 5100 | 华沙 | 48 22 695 0050 |
| 休斯顿 | 1 713 220 6700 | 费城 | 1 215 851 1000 | 惠灵顿 | 64 4 474 4400 |
| 香港 | 852 2101 6000 | 布拉格 | 420 2 210 83111 | 楚格 | 41 41 727 97 00 |
| 苏黎世 | 41 1 333 55 55 |
AMSTERDAM ..........31 20 5754 890 LONDON................ 44 20 7888 8888 SAN FRANCISCO... 1 415 836 7600 ATLANTA.................1 404 656 9500 MADRID.................. 34 91 423 16 00 SÃO PAULO ......... 55 11 3841 6000 AUCKLAND ...............64 9 302 5500 MELBOURNE .......... 61 3 9280 1666 SEOUL .................... 82 2 3707 3700 BALTIMORE ............1 410 223 3000 MEXICO .................... 52 5 283 89 00 SHANGHAI............ 86 21 6881 8418 BEIJING .................86 10 6410 6611 MILAN.......................... 39 02 7702 1 SINGAPORE ................ 65 538 6322 BOSTON ..................1 617 556 5500 MOSCOW ................ 7 501 967 8200 SYDNEY .................. 61 2 8205 4400 BUDAPEST ................36 1 202 2188 MUMBAI................... 91 22 230 6333 TAIPEI ................... 886 2 2715 6388 BUENOS AIRES ....54 11 4394 3100 NEW YORK.............. 1 212 325 2000 TOKYO .................... 81 3 5404 9000 CHICAGO.................1 312 750 3000 PALO ALTO............. 1 650 614 5000 TORONTO............... 1 416 352 4500 FRANKFURT...............49 69 75 38 0 PARIS ..................... 33 1 40 76 8888 VIENNA ..................... 43 1 512 3023 GENEVA..................41 22 394 70 00 PASADENA ............. 1 626 395 5100 WARSAW................ 48 22 695 0050 HOUSTON................1 713 220 6700 PHILADELPHIA....... 1 215 851 1000 WELLINGTON........... 64 4 474 4400 HONG KONG ............852 2101 6000 PRAGUE................ 420 2 210 83111 ZUG ........................ 41 41 727 97 00 ZURICH .................... 41 1 333 55 55
版权所有,瑞士信贷第一波士顿银行及其子公司与关联公司,2000 年。保留所有权利。
Copyright Credit Suisse First Boston, and its subsidiaries and affiliates, 2000. All rights reserved.
本报告并非面向或意图发给位于任何地区、州、国家或其他司法管辖区的公民、居民或在当地居住的任何个人或实体使用,前提是此类分发、出版、提供或使用会违反相关法律法规,或导致瑞士信贷第一波士顿银行或其子公司、关联公司(合称“CSFB”)需要在该司法管辖区进行任何注册或许可。除非另有明确说明,本报告中呈现的所有材料均归 CSFB 版权所有。未经 CSFB 事先明确的书面许可,不得以任何方式修改、传输或向任何其他方分发任何材料、其内容或其任何副本。本报告中使用的所有商标、服务标志和标识均为 CSFB 的商标、服务标志或注册商标、注册服务标志。
This report is not directed to, or intended for distribution to or use by, any person or entity who is a citizen or resident of or located in any locality, state, country or other jurisdiction where such distribution, publication, availability or use would be contrary to law or regulation or which would subject Credit Suisse First Boston or its subsidiaries or affiliates (collectively "CSFB") to any registration or licensing requirement within such jurisdiction. All material presented in this report, unless specifically indicated otherwise, is under copyright to CSFB. None of the material, nor its content, nor any copy of it, may be altered in any way, transmitted to, or distributed to any other party, without the prior express written permission of CSFB. All trademarks, service marks and logos used in this report are trademarks or service marks or registered trademarks or service marks of CSFB.
本报告所提供的信息、工具和材料仅供您参考之用,不得用作或被视为出售、购买或认购证券或其他金融工具的要约或要约邀请。瑞士信贷第一波士顿银行未采取任何措施,以确保本报告提及的证券适合任何特定投资者。
The information, tools and material presented in this report are provided to you for information purposes only and are not to be used or considered as an offer or the solicitation of an offer to sell or to buy or subscribe for securities or other financial instruments. CSFB has not taken any steps to ensure that the securities referred to in this report are suitable for any particular investor.
本报告中提供的信息和观点,来源于瑞士信贷第一波士顿银行(CSFB)认为可靠的来源,但 CSFB 对其准确性或完整性不作任何陈述,且在法律及/或法规允许的范围内,CSFB 对因使用本报告所载材料而产生的损失不承担任何责任。本报告不可替代独立判断。CSFB 可能发布过与本报告所载信息不一致、或得出不同结论的其他报告。那些报告反映了其编写分析师不同的假设、观点和分析方法。
Information and opinions presented in this report have been obtained or derived from sources believed by CSFB to be reliable, but CSFB makes no representation as to their accuracy or completeness and CSFB accepts no liability for loss arising from the use of the material presented in this report where permitted by law and/or regulation. This report is not to be relied upon in substitution for the exercise of independent judgment. CSFB may have issued other reports that are inconsistent with, and reach different conclusions from, the information presented in this report. Those reports reflect the different assumptions, views and analytical methods of the analysts who prepared them.
在法律允许的范围内,瑞信第一波士顿银行(CSFB)可能参与或投资于本报告所述证券发行人的融资交易,为该等发行人提供服务或招揽业务,和/或持有该等证券或期权的头寸或进行交易。此外,它可能为本次报告材料中提及的证券提供做市服务。在法律允许的范围内,CSFB 可能在材料出版之前,依据或使用本文呈现的信息、意见,或其研究或分析。在过去三年内,CSFB 可能曾担任本报告提及的任何或所有公司公开发行证券的主承销商或联合主承销商,或者目前可能为该等证券提供一级市场做市。如需更多信息,可来函索取。
CSFB may, to the extent permitted by law, participate or invest in financing transactions with the issuer(s) of the securities referred to in this report, perform services for or solicit business from such issuers, and/or have a position or effect transactions in the securities or options thereon. In addition, it may make markets in the securities mentioned in the material presented in this report. CSFB may, to the extent permitted by law, act upon or use the information or opinions presented herein, or the research or analysis on which they are based, before the material is published. CSFB may have, within the last three years, served as manager or co-manager of a public offering of securities for, or currently may make a primary market in issues of, any or all of the companies mentioned in this report. Additional information is available on request.
过往业绩不应被视为未来业绩的指标或保证,对于未来业绩,没有任何明示或暗示的陈述或保证。本报告所含的信息、观点和估计,反映的是瑞信第一波士顿(CSFB)在最初发布之日的判断,并可能随时发生变化。本报告提及的任何证券或金融工具的价值及收益,均可升可降,且受汇率波动影响,这可能对此类证券或金融工具的价格或收益产生正面或负面影响。投资于诸如美国存托凭证(ADR)等价值受货币波动影响的证券的投资者,实际上承担了这一风险。
Past performance should not be taken as an indication or guarantee of future performance, and no representation or warranty, express or implied, is made regarding future performance. Information, opinions and estimates contained in this report reflect a judgment at its original date of publication by CSFB and are subject to change. The value and income of any of the securities or financial instruments mentioned in this report can fall as well as rise, and is subject to exchange rate fluctuation that may have a positive or adverse effect on the price or income of such securities or financial instruments. Investors in securities such as ADRs, the values of which are influenced by currency fluctuation, effectively assume this risk.
结构化证券属于复杂金融工具,通常涉及高风险,仅面向能够理解并承担相关风险的成熟投资者发售。任何结构化证券的市场价值都可能受到经济、金融和政治因素(包括但不限于即期与远期利率及汇率)、剩余期限、市场条件及波动性、以及发行人或参考发行人的信用质量的影响。有意购买结构化产品的投资者,应自行对该产品展开调查分析,并就购买行为所涉风险咨询自身专业顾问。
Structured securities are complex instruments, typically involve a high degree of risk and are intended for sale only to sophisticated investors who are capable of understanding and assuming the risks involved. The market value of any structured security may be affected by changes in economic, financial and political factors (including, but not limited to, spot and forward interest and exchange rates), time to maturity, market conditions and volatility, and the credit quality of any issuer or reference issuer. Any investor interested in purchasing a structured product should conduct its own investigation and analysis of the product and consult with its own professional advisers as to the risks involved in making such a purchase.
本报告在欧洲地区由瑞士信贷第一波士顿(欧洲)有限公司分发,该公司在英国受证券与期货管理局(SFA)监管。根据 SFA 规则的定义,本报告不面向个人客户分发。本报告在美国由瑞士信贷第一波士顿公司分发;在加拿大由瑞士信贷第一波士顿证券加拿大公司分发;在巴西由瑞士信贷第一波士顿加拉蒂亚投资银行分发;在日本由瑞士信贷第一波士顿证券(日本)有限公司分发;在亚太其他地区由瑞士信贷第一波士顿(香港)有限公司分发;瑞士信贷第一波士顿澳大利亚股票有限公司;瑞士信贷第一波士顿新西兰证券有限公司;瑞士信贷第一波士顿新加坡分行;在世界其他地区则由经授权的关联机构分发。
This report is distributed in Europe by Credit Suisse First Boston (Europe) Limited, which is regulated in the United Kingdom by The Securities and Futures Authority (“SFA”). It is not for distribution to private customers as defined by the rules of The SFA. This report is distributed in the United States by Credit Suisse First Boston Corporation; in Canada by Credit Suisse First Boston Securities Canada, Inc.; in Brazil by Banco de Investimentos Credit Suisse First Boston Garantia S.A.; in Japan by Credit Suisse First Boston Securities (Japan) Limited; elsewhere in Asia/Pacific by Credit Suisse First Boston (Hong Kong) Limited;. Credit Suisse First Boston Australia Equities Limited; Credit Suisse First Boston NZ Securities Limited, Credit Suisse First Boston Singapore Branch and elsewhere in the world by an authorized affiliate.
在 CSFB 未注册或未获证券交易牌照的司法管辖区内,交易将仅依据当地适用的证券法规执行,这些法规因司法管辖区不同而有所差异,且可能要求交易必须符合相关注册或许可要求的豁免条件。非美国客户如希望执行交易,应联系所在司法管辖区的 CSFB 实体,除非当地法律另有规定。美国客户如希望执行交易,仅应通过联系美国境内的瑞士信贷第一波士顿公司(Credit Suisse First Boston Corporation)代表进行。
In jurisdictions where CSFB is not already registered or licensed to trade in securities, transactions will only be effected in accordance with applicable securities legislation, which will vary from jurisdiction to jurisdiction and may require that the trade be made in accordance with applicable exemptions from registration or licensing requirements. Non-U.S. customers wishing to effect a transaction should contact a CSFB entity in their local jurisdiction unless governing law permits otherwise. U.S. customers wishing to effect a transaction should do so only by contacting a representative at Credit Suisse First Boston Corporation in the U.S.
NI2571.doc
NI2571.doc
此文最初发表于《万维网的成长动态》一文。作者为 B.A. 胡伯曼和 L. 阿达米克。
1 This was initially reported in “Growth Dynamics of the World-Wide Web.” Huberman, B.A., Adamic, L.
《自然》杂志第 401 卷,1999 年 9 月 9 日刊。此后,研究结论在《网页中的图结构》一文中被再次确认。作者:Broder、Andrei 等人,IBM 阿尔马登研究中心,加利福尼亚州圣何塞,2000 年 6 月。
Nature Vol. 401, September 9, 1999. Since then the results have been reconfirmed in “Graph Structure in the Web.” Broder, Andrei et. al. IBM Almaden Research Center, San Jose, CA., June 2000.
2 同前引书。胡伯曼。值得注意的是,观察到的幂律行为源自所有网站的访问日志,而非仅限于商业网站。公司战略能够影响其跻身前列的能力。
2 ibid. Huberman. It’s important to note that the observed power law behavior was derived from usage logs for all Web sites, not usage logs for commercial Web sites alone. Corporate strategy can influence the ability to crack the line-up.
有 6 家公司的财产被仍位居前 25 名的竞争对手(4 月份数据)吸收。其余公司仍位居前 100 名。
3 Six properties were absorbed by competitors that remained in the top 25 in April. The balance of the firms remained in the top 100.
4 迈克尔·莫布森、亚历山大·谢伊、斯蒂芬·卡瓦加,《绝对权力》,瑞士信贷第一波士顿股票研究,1999 年 12 月 21 日。
4 Michael Mauboussin, Alexander Schay, Stephen Kawaja, “Absolute Power,” Credit Suisse First Boston Equity Research, December 21, 1999.
尽管我们未能发现网站流量与市值之间存在直接的统计相关性,但在网站流量排名前 25 的公司中,有 14 家也位列市值前 25 名。
5 Although we could find no direct statistical correlation between site traffic and market capitalization, 14 of the top 25 companies in terms of site volume were also in the top 25 in terms of market value.
6《万维网的增长动力学》,胡贝曼(B.A.Huberman)、阿达米奇(L.Adamic)著,《自然》杂志,第 401 卷,1999 年 9 月 9 日
7《网络中的图结构》,布罗德(Andrei Broder)等合著,IBM 阿尔马登研究中心,加利福尼亚州圣何塞,2000 年 6 月
8《功能增强的搜索引擎》,《自然》杂志,第 405 卷,2000 年 5 月 11 日,www.nature.com
9《网站的竞争动力学》,毛雷尔(Sebastian M.Maurer)、胡贝曼(Bernardo A.Huberman)著,施乐帕克研究中心,2000 年 3 月 17 日
6 “Growth Dynamics of the World-Wide Web.” Huberman, B.A., Adamic, L. Nature Vol. 401, September 9, 1999 7 “Graph Structure in the Web.” Broder, Andrei et. al. IBM Almaden Research Center, San Jose, CA., June 2000 8 “Souped Up Search Engines.” Nature Vol. 405, May 11, 2000 www.nature.com 9 “Competitive Dynamics of Web Sites.” Maurer, Sebastian M., Huberman, Bernardo A. Xerox Palo Alto Research, March 17, 2000.
10 Ibid
10 Ibid