The site http://www.undrln.com/ used to look like Hacker News except I think their color was yellow. It featured user-submitted links/articles and voting. It looks like they have significantly changed the site's format though.
I would say any design problems and questions could probably be engaged with pretty well here on Hacker News, I've spoken to many good designers through HN.
It's more of a start-up community then hacker one, designers are a strong part of that community.
Dribbble should be mentioned too. Dribbble is basically "teaser shots of what I'm working on", while Forrst is "can I get some feedback on things I'm working on?"
It should be noted that Forrst has developers posting code too (just not nearly as much as design)
[+] [-] keane|14 years ago|reply
[+] [-] mrkmcknz|14 years ago|reply
It's more of a start-up community then hacker one, designers are a strong part of that community.
[+] [-] iqster|14 years ago|reply
[+] [-] polyfractal|14 years ago|reply
It should be noted that Forrst has developers posting code too (just not nearly as much as design)
[+] [-] mkelley82|14 years ago|reply
[+] [-] waru|14 years ago|reply
I used to enjoy conceptart.org, too, but haven't checked it much lately.