Until another service comes along that allows users to record which songs they've listened to, and be as ubiquitous (there's a Last.fm plugin of some sort for practically every music software player, and even for some hardware players), I think Last.fm is safe. With services such as Spotify competing with it, though, I think Last.fm has lost its chance in the music streaming industry. I have plenty of friends with Sp…
See http://libre.fm/
The site does bad job explaining itself, and therefore only makes sense if you already use last.fm. The UI is crude (javascript links with 'href="#"' which bounce you up to the top of the page all the time, etc) and inconsistent (nav bars come and go).
I think it's an awesome idea, but I think it needs some TLC from a good web developer. (And to be fair, here, I don't claim that I could do any better -- I'm bad at web UIs, and lean heavily on others when I have to make them.)