I've been on flickr 'til yesterday, and struggled to get the little audience I manage to get together. It's been frustrating. I think that those who have great audiences, besides having good pictures, of course, spend a ridiculous amount of time on the site commenting and fav'ing and doing whatever they can to get attention.
There are a number of great photographers there that go completely unknown. Flickr, I think, does not favour the discovery of talent, and it leaves it all up to you. You, who just want to care about your pictures.
After two days here on dA I must say I am enjoying it a lot as it is really simple to get in touch with others and to have other to see your work.
I've had my pics fav'ed as soon as I uploaded them without doing ANYTHING, and that is one of the most encouraging things that can happen to an artist: spontaneous feedback! Of course it's been a pleasure for me to do the same with other artists.
So, thanks dA, I hope not to become too dependant on you because it's easy to waste money here