I'm looking through user lists, and there are tons and tons of users who posted in the first couple of months who then immediately dropped off the site completely. What happened and is it possible to get them back? Semaphore is a notable absence, since he was a moderator pro tempore (and left after someone asked for a link to a translation?) and still ranks in the top 10.
In fact, of the top 10, five haven't asked a question or given an answer since at least October (with a few going back to July or even May). I can't see comments or votes, so it's difficult to tell activity, but those aren't great number regardless.