I recently deleted my account on last.fm. ^^"
Mostly because I didn't use the site anymore. I used it pretty much when I registered, but then, somehow, it wasn't that special anymore. I used to see who listens to what kind of music and stuff, but... that became boring.
And then I didn't want anyone to see what I'm listening to anymore. And some strange people wrote messages to me every once in a while. (Mostly people who weren't able to write proper English... which annoyed me. I mean, my English isn't 100% either, but... hell, these guys didn't even know about sentence structures AT ALL. <_<")

But I have to admit that last.fm was a good site and pretty useful. ^^
(I deleted my accounts on many many sites recently. ^^")