It's perhaps not as strange as Cisco (makers of fine computer network equipment) buying Tribe.net, but it's still a bit of a leftfield transaction. Last.fm vies with Pandora as the best way to get you music recommendations with dynamic playlists, analyzing music you play in various players automatically.
Being acquired by Fox hasn't seemed to slow down MySpace, outside of some folks migrating to Facebook. Unless they start dropping Paul Shaffer in behind MF Doom in my playlist, it's hard to see any major changes. As this CNet article points out though, this may give Last.fm the deep pockets to pull it through any Internet radio fee hikes. Pandora has a bit more momentum behind it, at least in terms of being included by phone carriers like Sprint, but this may give the service a boost when it comes to developing new features.