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Most Web pages can be connected in 19 clicks, study says

In this Friday, Aug. 5, 2011, photo, a young couple shares a computer to browse Facebook at an Internet cafe in Jakarta, Indonesia. (Tatan Syuflana/AP)

The Web can seem unfathomably vast, but according to a study published in the Philosophical Transactions of the Royal Society, it’s more tightly bound than you might think.

Most Web pages can be connected in 19 clicks or less, thanks to search engines, large aggregators and social networking sites, according to a paper on network science by Hungarian physicist Albert-László Barabási. As the Smithsonian magazine reported, these sites act as hubs for the Web at large — or, as Smithsonian’s Joseph Stromberg puts it, the “Kevin Bacons” of the Web.

While the vast majority of Web pages have few connections except to pages that have closely related content, the presence of these super sites pulls those disparate groups together. And that number doesn’t seem likely to change any time soon. As Mashable noted, others have highlighted the 19-click separation in the past, including a 2005 Web site actually called “,” but the new research shows that the number holds true in small- and large- scale tests.

Nineteen degrees of separation may be far more than the six that anecdotally connect Kevin Bacon to other Hollywood figures or the 4.84 that — at least in 2011 — connected most Facebook users on the company’s network. Yet considering the more than 14 billion estimated pages on the Web, a number under 20 is nothing to sneeze at.

Before you get warm, fuzzy feelings about the world being smaller than you think it is, however, Stromberg also notes that the paper highlights that having such a connected Web carries its own security risks. As Friday's hack disclosure from Facebook shows, even well-protected Web sites fall prey to attacks on occasion. Having a few, central hubs for the Web also means that successful cyberattacks on those sites can have wide-reaching impact.

(The Washington Post Co.’s chairman and chief executive, Donald E. Graham, is a member of Facebook’s board of directors.)

More technology news from The Washington Post:

Report ties 100-plus cyberattacks on U.S. computers to Chinese military gets official, will replace Hotmail

AP: Burger King Twitter account back up after Monday afternoon hacking; company apologizes

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Hayley Tsukayama covers consumer technology for The Washington Post.



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