Spotify is here in the US. And it's either gonna blow everything away or get shut down in a matter of weeks. While it's still invite only (unless you pay), it seems to marry the functionality of iTunes, Rdio, Pandora, and more in its client software, which smartly detects music on your computer and shares it with the world. Which is good, because that means you can pretty much listen to whatever you want. It's also bad because... well, for obvious reasons. I think that anything that exists on any of my iTunes playlists is now being shared with other Spotify users, and while I can change that setting, it's still a little unnerving.
But still! Tons of music. To listen to. For free. It feels a little like the wild west right now, and suffers from the problems that things like Napster and Kazaa had—bad tags, mostly, from other users—but jesus. Everything people said about it is true. Not everything is on there, not even close (and I had no luck finding upcoming, not-yet-released records from Portugal. The Man and Blind Pilot—thankfully, because cans and cans of worms) but there is plenty. The best feature seems to be the ability to send music directly to your friends, which could replace things like Mediafire and Dropbox and old fashioned mixtapes.
If the government doesn't shut this whole thing down. Which it probably should.