Facebook is literally MySpace's baby brother, launching three months after the #1 social network, in February 2004. But it wasn't until September 2007 that the platform became accessible to folks outside of the .edu domain. First ten corporations, including Accenture, Apple Inc., Intel, PepsiCo, and Microsoft, were invited to build networks within. Then - BAM - anyone who had a valid e-mail address. At that point there were eight million regulars in the Facebook community. Nine months later, there are 23 million. And it continues to grow by 100,000 registered users a day.