A report released by Hitwise yesterday revealed that MySpace received 72 percent of the United States\u2019 overall Web traffic from the 10 largest social networks in December 2007. But Facebook, which came in second with 16 percent, remains the fastest-growing social network.\n\nRELATED LINKS\nWhat "Secret Crush" Widget Can Teach Business About Managing Facebook\n\nLinkedIn Opens Site to Developers, Jazzes Up Design\n\nBusiness Lessons from the Widget Masters\n\n\tThe report measured the market share of social networking sites by calculating how many \u201cvisits\u201d they received in December 2007 compared to the year before. A visit is defined as Web traffic directed at a domain or category of a social networking site. \n\n\tFalling into third and fourth were Bebo and BlackPlanet, which both received around 1 percent. \n\n\tThe report painted a mixed picture for MySpace. In December 2007, about 95 percent of the site\u2019s visitors were return users\u2014people who had visited the site at least one other time in the same 30-day period\u2014indicating a loyalty among its users. In addition, MySpace saw users spend an average of 29 minutes on the site, while Facebook trailed at 19 minutes. The one caveat: That was a nearly 10-minute increase for Facebook, while MySpace (which had 30 minutes last year) saw a slight downturn.Where the Social Networking Eyeballs Go\nThe latest Hitwise report shows the market share of the top 10 social networks and the year-over-year growth rate.\n \n \n\n \n\n \n \n\n\nRank \nName\nDec '07\nDec '06\n% change\n\n\n1\nMySpace\n72.32%\n78.89%\n-8%\n\n\n2\nFacebook\n16.03%\n10.59%\n51%\n\n\n3\nBebo\n1.09%\n.99%\n10%\n\n\n4\nBlackPlanet\n1.04%\n.96%\n8%\n\n\n5\nClub\u00a0Penguin\n.80%\n.54%\n48%\n\n\n6\nGaiaonline.com\n.76%\n.58%\n31%\n\n\n7\nMyYearbook\n.73%\n.14%\n407%\n\n\n8\nhi5\n.63%\n.64%\n-1%\n\n\n9\nClassmates\n.55%\n.58%\n-7%\n\n\n10\nYahoo\u00a0360\n.54%\n.91%\n-40%\n\n\nSource: Hitwise\n\n\n\tNonetheless, both sites can use those numbers to help generate revenue from advertising. \n\n\t\u201cIt\u2019s a sign that [users] are coming back and interacting as much as possible,\u201d says Heather Dougherty, Hitwise\u2019s director of research. \u201cIf you\u2019re an advertiser looking to place media on the site, that\u2019s very attractive.\u201d\n\nBut MySpace also saw its growth rate shrink by 8 percent, paling in comparison to Facebook, which increased by 50 percent over last year. Jonathan Yarmis, an analyst with AMR Research, says those numbers indicate that Facebook has been able to evolve from a collegiate and high school phenomenon to engage a broader, older audience.\n\n\u201cThe growth rate says it all,\u201d Yarmis says. \u201cBy opening the platform, Facebook has seen a ton of growth from people who are not in the 20-something demographic. It\u2019s to the eternal consternation of my son, who is 16, that I, at 52, have more friends than he does [on Facebook].\u201d\n\nWhat wasn\u2019t immediately clear from the report was how many users entertain accounts in both Facebook and MySpace. Hitwise\u2019s Dougherty couldn\u2019t specify how many users had an account at both, but she did say that 7 percent of visitors to MySpace proceeded to visit Facebook immediately after. And 5 percent of Facebook users went to MySpace immediately after. \n\n\u201cA lot of people definitely have two accounts,\u201d she says. \u201cA lot of people are moving back and forth.\u201d\n\nYarmis says it will be interesting to see how MySpace and the other social networks stunt the growth of Facebook, which continues to get tons of media attention. Its founder, Mark Zuckerberg, just appeared on 60 minutes on Jan. 12.\n\n\u201cThe interesting question is, What does everybody else do?\u201d Yarmis says. \u201cIs OpenSocial the rallying platform that allows a combination of sites to deliver something competitive to Facebook? We\u2019ll have to see.\u201d\n\nEditorial Assistant Jarina D'Auria contributed to this report.