[Leon]

I use Soulseek if I'm specifically looking for something.

I check forums like these to check out new artists. Nice thing about this forum is that the tastes are quite versatile.
Then there are some blogs I read and newsletters I receive over e-mail.
And last but maybe most important: Whenever I listen to an artist, I go to Discogs.com, check what lable he's on, check out other artists from that lable and so on...