Myspace is still king of the hill, but has seen slow growth at only 1% year over year to 59.3 million users; while Facebook has grown 116% year over year to 39 million users.

You can read more about it at cnet. So if you’re doing internet marketing or just interested you should probably have at least a myspace, and facebook account if you’re interested in leveraging social networks. And if you’re more adventerous you might want to try out twitter, linkedin as well as some of the other services that are listed in the press release.