Traffic monitoring company HitWise reports Facebook logged 58.6 percent of all US visits among 155 social networking websites in September 2009. The social networking site saw its traffic rise by 194 percent compared September 2008. Twitter did even better, traffic to the micro blogging site skyrocketed by 1,170 percent. More details at eWeek.
It's official: Facebook is soundly thrashing one-time social network leader MySpace, though the site credited with kickstarting the mainstream social networking gold rush was far and away the No. 2 social site. Tagged was No. 3 at 2.4 percent of the September 2009 U.S. share, with Twitter and MyYearbook rounding out the top five social site ranks, grabbing 1.8 percent and 1 percent share, respectively.
Twitter boasted astronomical growth, up 1,170 percent from its negligible .15 percent market share from September 2008. As far as social sites go, Twitter is positioned to be Facebook's biggest challenger.