Facebook undisputed leader

Facebook is still the undisputed leader the U.S. social networking market with 166 million unique visitors in November. comScore, leader in measuring digital world has published this information.

The average user spent 6.6 hours per person engaged on the site during the month, an increase of 37% in the past year. These outsized audience and engagement numbers should not be a surprise to anyone at this point. 

Courtesy - comScore

Meanwhile, Twitter.com and Linkedin.com have been jockeying over the past several months for the #2 spot in audience size. 

In November, Twitter eked out the second position with 35.4 million unique visitors, just slightly ahead of Linkedin with 35 million. 

Myspace currently owns the #4 position with 25 million visitors, but it has seen a steady decline in audience over the past two years.