I've reviewed all the sites listed on TechCrunch's Social Music review by Seattle blogger Ryan Stewart, who I met last year at the Venture All Stars Event. Congrats on getting to TechCrunch status Ryan!
I'm a huge fan of electronic dance music, as are many others involved in technology, and I was excited to find some new artists I hadn't heard of. I thought their may be an up and coming artist somewhere in Europe that I had never heard of. So I was very surprised to find that after going to each site, I had a lot of trouble finding an artist I had never heard of, these were all the top 100 dj's in the world.
All these services (at least in electronic music) seem to largely ignore the long tail of music and those purveyors of it. Popular artists are great, but how do I find out about the new stars? MySpace seems to have figured out how to promote new artists, why can't these services? I absolutely love the feeling of listening to the latest and greatest, so someone should look into this service.
I think their is a wide open market for a social music service that recommends newly or semi popular artists and integrates them with popular artists. Granted a lot of the long tail sucks, but there must surely be at least one artist that's great and not huge but growing for each artist that is huge. Why isn't anyone doing this yet?