For me, the quality of dribbble has declined a lot the last couple of months. (Your theories are as good as mine.)
The good artists seem fewer and farther between, and where I would also have looked to dribbble before, it just feels like yet another social link to add to your digital CV rather than a place companies trawl for talent.
Bryce, you need to get WAY higher to make this a worthwhile deal. assume you lose half your traffic once they stop promoting it. you still have a decent sized mailing list, so you can sell to those guys, but they might not upgrade once the traffic dies off.
It does go to show. With only 200 paying customers, they're making 20,000$/month!