C.K., you reminded me of a question I've had: should I be "logging out" (off)? I always just close the window.

I don't think that it matters whether you log out or not. The Who's Online box says that it only shows users who have been active in the last ten minutes.
I often don't log out myself. It's easier to just jump back in than to take 5 whole seconds to log in when I arrive.