I’m pretty sure I already knew that hyperlinks and web traffic followed a power law distribution, but Brian’s explanation is clear and worth saving down for future reference.
Another possibility is that the Internet might not be so egalitarian after all. To understand why this would be, it’s necessary to reflect on the structure of the web. The element tying one web page to another is the hyperlink. Clicking a hyperlink is what allows an Internet user to “browse” from one web page to another. Across the web, hyperlinks follow a power law distribution . A power law distribution is highly inegalitarian; this means that a small number of web sites are the destination of the vast majority of hyperlinks.
The distribution of traffic to web sites also follows a power law. To understand why this should related to the hyperlink structure, it’s necessary to think about the ways Internet users discover web sites. If a user already knows about a web site, they can visit it directly. If they don’t, they can discover it via a hyperlink from a site they already know about or by using a search engine like Google. Both of these methods favor the discovery of highly linked-to sites. When browsing the web, the more hyperlinks there are to a site the more likely a user is to come across one of them. When using a search engine, most users only visit web sites on the first page of results. The release of search data for over 600,000 AOL users showed that 90% of clicks went to the results from the first page, 74% of clicks went to the first 5 results, and 42% of clicks went to the first result. This is significant because search engines’ rating algorithms give heavy weight to the number ofhyperlinks a site receives. Although the exact algorithms vary from search engine to search engine and are often secret, search engine result ordering is barely distinguishable from simply ordering web sites based on the number of hyperlinks to them.