Facebook bested Web giants Google, Yahoo and Microsoft in time spent online in the United States through 2010, with users spending 12.7 percent of their time at the social network Website.
Facebook users logged 49.4 billion minutes, up 79 percent from 2009, while total page views grew 71 percent to 76.8 billion, according to comScore's "2010 U.S. Digital Year in Review study." Facebook accounted for 10 percent of U.S. page views in 2010.
Google Sites and Yahoo Sites remain the most trafficked Web properties in the country, with 180 million visitors each month. Facebook's U.S. audience grew to 153.9 million in December, an increase of 38 percent from December 2009.
However, with 600 million-plus users actively hobnobbing on the site from desktops, latops, tablets and mobile phones, it's no stretch to think Facebook won't pass the Web powers in popularity for 2011.
The user engagement stat is particularly important for Web companies who rely on consumers to view or even click on ads.
Facebook has said its users are spending an average of 20 minutes per day on its Website, which means users are exposed to more of the company's targeted display ads. EMarketer said these ads earned the company $1.86 billion in ad sales last year.
Facebook is also testing Sponsored Story ads to boost ad relevance, helping businesses better connect with their consumers.
Facebook isn't the only social site enjoying big traffic. Social networking sites accounted for 12 percent of all time spent online in 2010 with the average Internet user spending more than 4 sites each month.
Specifically, LinkedIn emerged as the third largest social network site with 26.6 million visitors, while Twitter.com climbed 18 percent to 23.6 million visitors, excluding visitors from third-party and mobile apps. Startup Tumblr hiked168 percent to 6.7 million monthly visitors.
"It is clear that social networking has become an integral part of the fabric of the Internet and one that is increasingly becoming integrated into the experience of so many different activities online," comScore noted.
What should alarm Google, Yahoo and Microsoft about the trend, which Facebook epitomizes best, is that none of the trinity of Web rivals have a such a strong, fast horse in the social network race.
Microsoft and Yahoo prefer to integrate with Facebook for their social utilities, while Google has yet to provide a serious social component to lure users.
Google + 1, the search engine's offering in this arena, is allegedly coming later this year, by which time Facebook will have lengthened its market and social ad lead.