Facebook has seen an impressive bump in traffic versus this time last year. For September 2009, the site claimed 58.6 percent of U.S. social networking tracking, a jump of 194-percent over the same period last year. Twitter's increase, meanwhile, was downright absurd, jumping 1,170 percent over the past year.
In September 2008, Facebook recorded a 19.94 share, which increased to 58.59 percent for Sept. 2009. MySpace, by contrast, dominated the social-networking sites last September, with a 66.8 percent share. Since then, however, MySpace's market share has plunged to 30.3 percent, still leaving it second in U.S. traffic.
(Source: PC Magazine)