While I have to say it would depend somewhat on the purpose of the forum in question, my default response is no. Generally speaking I post on forums that have to do with fiction, fantasy and games and do so using names relevant to characters active in those settings (in most cases the same username). My opinions on the latest class changes in Random MMO or the possibility of applying values from Generic Fantasy Series to Hypothetical Scenario don't have much bearing on my real life. I'm quite happy to maintain distance between these things.