After quite a lot of searching, I haven't really find that many websites focused on design critique, where you could just upload your work and get some responses.
One of the biggest sites oriented on artsy people is probably DeviantArt, which is really great, but it is nearly impossible (at least for me) to get some relevant critique on newly added work.
The problem that I see with sites like DA is that they don't reward the people who comment/rate/critique.
On StackExchange we have the Karma system, as people get little points when they post a good answer, which greatly enhances the community to be active.
Is there any such a site for designers, where it doesn't take milion years to get a response for newly uploaded stuff? The only one I was able to find is Dribbble, which however is a invite-only service.