MySpace is popular because it’s chaotic and allows you to do what you feel like without much structure. You can do what you want where you want to do it. It’s like IM gone mental, with the output stored for future reference.
Friendster was more structured and lost popularity for that reason, as well as having a hostile administrator and slow system response for a long period of time… but it was a lot more structured.
Anyone who thinks that the up-and-coming generation are tech-whizzes who can do great things with technology should take a look at MySpace as a counter-example. They’re just consumers of what’s put in front of them, and that’s about the extent of it.