Not really sure. The websites are very different. For most people over the age of 15 Facebook is a place for actual friends. Myspace is different in the sense it's cool or common to have a bunch of people you don't actually know. While you can limit profiles on facebook, there is a lot more personal content so people are more careful to add people. Also, considering it was originally university students, getting 100-500 friends you actually know isn't that hard, which nullifies the need for 'internet friends' I know that didn't really answer it, but I think even if there was one it wouldn't be that effective.
well i set up a page for my site, which has around 130 fans .... and then on my main page i got around 450 .... it would just be great if you could reach you limit of inviting people each day far quicker