I - spending most of my waking hours dealing with network security in some fashion - know quite well that there's very little true privacy online.
However, the "reputation" question is - to me - much more interesting. While I don't really care what people think of me, I tend to portray myself (both in real life and on here) in a certain fashion: a knowledgeable guy, fun to hang out with, lots of crazy ideas, and so on. As such, I have built myself a repuation (don't know if I succeeded in all that I've gone for, but it's a start, I'm sure). Anyone who posts, whether they mean to or not, builds a reputation in the minds of others. After that, it's a question of whether they ensure that the reputation is a good one or "some weird guy posting on a forum I read."
My two cents
