Looks like Discogs also as an API.
It's probably no-go since it's nonfree, but Last.fm does have an API. I'm not sure if its artist db is more accurate than Wikipedia, though.
That looks great, especially since you can use Maloja as a proxy to forward scrobblings to other services too. I vote for supporting it!
Now that we have ratings (hooray!), it'd be great to have configurable keyboard shortcuts for them too.