Web: 19 Degrees Of Separation?

Any two randomly picked pages on the World Wide Web are, on average, just 19 clicks away from each other, researchers say.

The findings, reported in Thursday's issue of the journal Nature, suggest that the Web is so interconnected that any desired information is nearby even though there are 800 million documents available. The key is knowing which links to click.

The study calls to mind the movie and Broadway play Six Degrees of Separation, which holds that all people are connected to one another by no more than six individuals, and the party game Six Degrees of Kevin Bacon, in which players try to make a connection between actor Kevin Bacon and another celebrity using six or fewer other stars and movies.

The study was conducted by Albert-Laszlo Barabasi, a University of Notre Dame physics professor, and colleagues.

They constructed a robot that collected all the links on a Web page and followed them to their destination. The process was repeated over and over again.

Using statistical tools, they figured out the average distance between two random pages. And even if the Web grows 1,000 percent, the distance would change only from 19 clicks to 21.

Search engine companies could use the findings to create programs that more intelligently figure out what's available. A recent study showed that even the best search engine scours only about 34 percent of the Web.

"Knowing something about the topology lets you know how far you need to go to catch something that might be out there," said Steve Lawrence, a researcher at the NEC Research Institute and co-author of a previous study on the effectiveness of searches.

"The search engine companies are going to benefit from this kind of knowledge," he added.