At PhotoSIG, you can upload photos and have them critiqued by the resident community. The site seems to be thriving; the imagery is of a very high quality and many of the critiques are extremely helpful & constructive. A key to the success of the community is limiting the number of photos you can upload. Photos and critiques deemed thumbs-up give you more points; more points equals more photo uploads allowed.
This is boosted by the innovative Last Chance Critic system which ensures that each photo is reviewed at least three times. So sign on and give some of my photos a triple thumbs-up. (Thanks to Marcus.)