I just signed up for an account yesterday. It's a music hosting site, meant to rival Myspace. They do some things better (you can upload 2 hours' worth of music), and some things worse (the free account allows unlimited streams, but only 100 downloads per song?!).
What I really think is cool, though? You can comment on specific parts of a song. That is: say I upload a song (I haven't yet). It displays as a wave form, in the player, so you can visually see peaks and valleys and all that. There's a bar at the bottom of it, allowing you to click anywhere in the song and add your comments for everyone to see.
For anyone on these forums that asks for advice, or is looking to collaborate with people online, I think that this is powerful, ingenious, and really simplifying. There's an example of that right here (it's at the bottom, under "The Modernist").
Ok, bye!