Despite growing privacy concerns, an astonishing 540 million Internet users worldwide visited Facebook in April 2010, or 35.2% of the entire population of Web users, according to new data from Google. Even more incredibly, those users clicked on 570 billion Facebook pages in April, a number eight times larger than Facebook's nearest competitor.

Ten of the World's Strangest Social Networks

The new figures come from Google's DoubleClick Ad Planner, and rate the top 1,000 most-visited sites on the Web (excluding Google itself, YouTube and Gmail).

Yahoo came in second place after Facebook, with 490 million unique visitors, 31.8% of the world's Internet-connected population, and 70 billion page views. Next was Microsoft's Live.com, with 370 million unique visitors and 39 billion page views.

Illustration: Steve Lyons The most popular sites after Live.com were Wikipedia, MSN.com, Microsoft.com, Blogspot.com, Baidu.com, GG.com and Mozilla.com.

The numbers show that Facebook is the undisputed king of social networking, with rival Twitter attracting a comparatively modest 96 million unique visitors and 5.4 billion page views in April 2010.

Facebook has courted controversy with new privacy settings that have made it difficult to hide personal information, and users have threatened to shut their Facebook accounts down. More than half of Facebook users are considering dumping their Facebook accounts because of privacy concerns, according to one poll by Sophos.

But the threats may ring hollow when looking at Facebook's actual web traffic. In the United States Alone, Facebook attracted 135 million unique visitors in April 2010 -- 43% of the total U.S. population -- compared to 145 million for Google, according to separate data released by Compete, an analytics firm.

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This story, "Facebook Traffic Tops, Google Reports" was originally published by Network World .