I don't post too often on any of the groups that I am signed up for, mostly just a lack of spare time on my part. My big passion lately is Doctor Who and wouldn't you know it...they have a group here, lol! I think that is where I post most often but usually nothing about my weight.
When I first started, I signed up for probably 25 groups and trimmed that down quite a bit since then. Mostly I just read on the groups when I have a bit of spare time and blog when I can.