If you mean like review sites or sites that showcase music (not like.. spotify for grooveshark right, not streaming/playing sites?) then I have a couple that I like to check out when I'm interested in new bands or whatever. These are mostly just indie rock so if that's not your thing you probably wont be interested:
KEXP Radio:
http://www.youtube.com/user/kexpradioRadio station in Seattle, there's some good bands here occasionally. They come play live in the station so it's pretty cool to me.. I like live music. Definitely hipster/indie though.
La Blogotheque:
http://www.youtube.com/user/LaBlogothequeBoth of these are just youtube channels but... I don't like to read reviews usually I just want to listen to it and decide for myself if I groove on it. Blogotheque is cool, live impromptu shows. There have been a lot of decent people playing on there, some more or less famous. Pretty good though. These bands tend to be more low-key than KEXP though that's mostly because they are always acoustic sets.
The Wild Honey Pie:
http://www.thewildhoneypie.com/These guys have more writings/reviews and intros to new stuff instead of videos, though there's usually always a stream/media player of some kind. Easily the most hipster but I find some decent bands here. There's a club here in Vegas called The Griffin (Griffon?) that's really cool, it's like all dark and wood and there's a bunch of fireplaces and stuff. The place is really awesome and for some reason a bunch of the music on there just reminds me of that place. Like I found
this song on there and it embodies the spirit of that perfectly and I guess I really dig it... it makes me want to get drunk and smoke a bunch of cigarettes in the dark with a bunch of sweaty kids packed around me... good times. I miss that place.
So yeah those tend to be the places I check up on every week or two to see if there's anything new that catches my attention. I recently found this band
The Joy Formidable on KEXP and I liked em a lot (if you watch that video doesn't she seem a little crazy? In a good way, but definitely crazy), got their album and it's surprisingly decent all the way through.
I found
Fang Island on KEXP too and I fell in love with that song for a long time. That performance is the best version of that song I've heard, it's better than the album version.