I have no clue why Sanus left, but he is welcome to pop into the forums whenever he wants!
To be honest, I really am not bothered if people come and go from forums. I mean, people have their own life, and their own stuff going on, and really its not as though we as a collective sit around wondering "where is forum member X?" all the time. Sometimes I'll think "whatever happened to so-and-so", but it really doesn't bother me one way or another.
What I find funny is when somebody who has been absent from the forums for a long time, are absent because they're afraid of how people will treat them if they return. Or because they think "my god I must have really offended everybody for being gone for so long! They'll only hate me if I return!" It's not an exclusive club, so no pressure at all!