Traffic data from research firms Hitwise and comScore show which social media sites are winning the popularity contest, reports MediaPost.  Hitwise data shows year over year growth is strongest for Facebook and Twitter, though Twitter’s astronomical surge is starting to level off.  MySpace has seen a plunge in its share of traffic.

According to Hitwise, Facebook drew more than 58 percent of total traffic to social networking sites it tracked.  The figure is a four-fold increase from last year.  The site is claiming it grew users from 250 million to 300 million in two months.  Meantime MySpace saw a social pariah level drop in its draw, plunging 55 percent to draw only about 30 percent of social media users this year.  For Twitter, data released by comScore shows the site leveled off to about 20 million users after more than quadrupling user base between February and April of this year.

MediaPost includes a chart breaking down Hitwise data for the top five social media sites.

Read more at MediaPost {link no longer active}.