Facebook stole the thunder from Google this year as the most-visited website in the United States, according to a new study from Internet research firm Experian Hitwise.

The social-networking juggernaut's www.facebook.com was the top-visited website for the first time and accounted for 8.93 percent of all US visits between January and November 2010, Experian Hitwise said.

Google, the world's Internet search leader, slid to second place. Google.com drew 7.19 percent of visits, followed by Yahoo! Mail (3.52 percent), Yahoo! (3.30 percent) and YouTube (2.65 percent).

Facebook led arch-rival Google in the number of hits per month since March.

However, taking into account all of Google's websites, such as YouTube and Gmail, the Mountain View, California-based company drew 9.85 percent of the US visits, ahead of Facebook's 8.93 percent and the 8.12 percent garnered by Yahoo! sites, an Experian Hitwise spokesman said Friday.

Online tracking firm comScore last week ranked the Yahoo! family of websites as the most-visited in the US in November, ahead of Google, Microsoft websites and Facebook.

On a global scale, Google held the top position, followed by Microsoft, Facebook and Yahoo!, according to comScore.

But analyst Greg Sterling of the specialist site SearchEngineLand.com cautioned that the Hitwise study does not track website visits via mobile devices such as cell phones or tablets, and the number of searches on Google's Chrome browser, which avoids google.com, was uncertain.

"This is right now more symbolic than anything" to see Facebook overtake Google in the United States, Sterling told AFP, adding that the study confirms "Facebook growth has been dramatic."

The social-networking giant has more than 500 million active users per month in the world, and according to comScore attracted 647.5 million unique visits in November, a jump of 48 percent from a year ago.

Sterling highlighted the sharply different approaches between Google and Facebook.

"Google is a very utilitarian site, where people go to make a decision, whereas Facebook is for entertainment," he said.

But if Facebook "were to concentrate on search, they could do something that stands to really hurt Google."