Yeah, Last.fm is really good for playing a playlist from a single scene. It's not necessarily a single genre, just bands who tour together, or guest on each other's tracks.

They used to go pretty deep too, like bringing in bands from 20 years before that influenced the current one.

It's not necessarily the greatest for bands that are selling out stadiums as there's too much interference from Clear Channel, but it's great for small to midsize scenes which tend to have shows from 100-1000, since those tend to be more defined.