I've only recently heard it as a non-gender-specific term for waiter or waitress - around here we use the term "server". I'm not sure if it's intended that way but to me it sounds like a robot (not sure why, it just does), somewhat demeaning. However, I've seen it used it contexts where it doesn't seem to be intended that way.
Is it just me? I think "server" is fine as a gender-neutral term, as is "waiter" (I've noticed that the media nowadays use "actor" to mean both male and female).