One in Four Americans Use MySpace

In other words MySpace boasts 70 million users, according to the latest from comScore.

Back in July of 2005, the social networking site was picked up by Rupert Murdoch's News Corp. for what was considered a hefty $580 million. Now some investors say it was a bargain.

So how many of those users are teens? Forrester Research says that nearly 80% are weekly MySpace aficionados, but Facebook is giving MySpace a run for the money.

Facebook, once a stranger to the under-18 crowd has swelled its user base two-fold while MySpace's under-18 visitors dropped by 30 percent over the past year.