Back in november I tried some myspace stuff, what worked for me was posting related content; like I would post family guy vids and stuff on a family guy profile...ect. This was probably when my site was at it's peak. I plan on trying it again but most high traffic profiles do not allow embed tags now.
I don't use it very much, but I do use it for my site bandoftheweek.com. I guess it's helped me out recruit bands for the weekly contest, but it's mostly a word of mouth site.