While facebook doesn't currently allow other widgets, you don't feel quite so "marketed to", and they do have a developer tool. Plus, a lot of the interest in MySpace was the ability to personalize - that's why most pages were virtually unreadable! Facebook is more of a true social interaction tool - with a tiny dash of voyeurism. I do hope they allow widgets at some point, however.
The greatest line against Web 2.0+ is the following:
At stake is the ability of MySpace, which is owned by the News Corporation, to ensure that it alone can commercially capitalize on its 90 million visitors each month.
Then a telling quote later on, talking about how MySpace is moving away from what made them successful:
If MySpace isn’t really ‘their space’ after all, maybe users will think about things differently.