Kyle Bragger was kind enough to answer a few question I had about Forrst, a feedback community for designers and developers that launched around 2009. Here's what he had to say:
KB: Probably a combination of keeping things focused, and balancing the membership growth with community growth. Things felt like they got off the rails from time to time in terms of the overall goal of the community, especially with people coming in and using it as though it were Dribbble etc. (i.e. posting low context previews of work) — it didn't give a lot to go on in terms of other people being able to give actionable feedback and critique. And with membership/community growth, as it was invite only, that naturally meant the community had room to breathe and grow somewhat organically, and generally (at least at first) kept the quality of membership high, but also mean that often people who should be members weren't.
KB: Probably a decline in the quality of the community. Many factors were at play, some folks thinking it was just a Dribbble clone and treating it as such, a skew of membership towards much younger people who weren't interested or able to participate and provide critique/help to others for various reasons, my eventual departure, etc.
KB: I think it was responsible for the overall quality & longevity of the community. It wasn't perfect but I think flooding the gates, to to speak, would have meant a lot more noise and self-serving posts.
KB: Probably not do it. :-) It was a great experience but I'm not sure I have the mental bandwidth to attempt to foster that kind of community again. I do have thoughts here and there about other ways I can build things which are helpful to our industry at large, but I'm not sure a feedback community is on that list any more.