MySpace.com averaged 76.35 percent of all US visits in 2007* in a custom category of 53 leading social-networking websites, followed by Facebook.com, Bebo.com and BlackPlanet.com with 12.57 percent, 1.24 percent and 0.87 percent, respectively, according to Hitwise, writes MarketingCharts.

The remaining 49 social networking websites in the custom category accounted for 8.97 percent of US visits, Hitwise said.

Among the Hitwise data released:

• In December 2007, MySpace.com received 72.32 percent of US visits among the social networking category, Facebook.com received 16.03 percent of visits and Bebo.com received 1.09 percent of visits.

• MyYearbook had the largest gain in market share in December 2007, increasing 407 percent compared with December of the previous year. Facebook and Club Penguin followed, increasing 51 percent and 48 percent, respectively.
• US traffic to all social-networking websites increased 4 percent year over year.

• In December 2007, MySpace received 95 percent of its share of traffic from returning visitors. Among the top five social-networking websites by market share, Facebook and BlackPlanet.com followed with 93 percent and 89 percent, respectively, of traffic returning from the previous month.

• In December 2007, the average time spent on Bebo led among the top five social-networking websites, with users spending an average of 30 minutes and 24 seconds on the website.
• Facebook experienced the largest growth in average time spent, increasing 100 percent in Dec. 2007 to 19 minutes and 51 seconds from just under 10 minutes in Dec. 2006.

* Data is based on averaging the monthly market share of US visits from Jan. 2007 to Dec. 2007.