I guess I am a mysterious one too,(sounds way cooler than a lurker) but even so, Renderosity and its generous members have been invaluable to me in advancing my knowledge of poser and digital art in general. I browse the galleries, the market place and the forums regularly, but post infrequently to the forums probably because I have no better information to add than has already been provided. I do always check the critique forum, as I think many artists, myself included, don't have a reliable venue to get constructive feedback on their work, but it is a vital part of any artists growth. I would love to see the critique forum used more and would post both my own work there, and readily comment on others.I think to critique someones work well is one of the most valuable things you can do for another artist. Even if its hard to here something you slaved on have all its flaws brought into the light, it means the next piece is better. having someone tell me whats right & wrong with my work, holds my interest and attention much more that someone simply saying "nice!" ( although "nice!" is good to here too) having a conversation about something you worked hard on and seeing it from someone elses perspective is also one of the most interesting things about making art in my opinion.
   I guess I always have a thought in my head  "I love renderosity, I should upload some props to free stuff/images to the gallery/mindless mental meanderings to the forum, but for whatever reason, I just get sidetracked and don't. I want to make an effort to change that, as this community is actually important to me, mysterious one though I may be.