If you're leaving, just go! People will figure out you're gone and adjust. It's much less painful that way.

We're going to have to agree to disagree on this one, Kilborn. If someone I interacted with on a regular basis just up and disappeared, I'd be a lot more pissed off than if they said, "Hey, I'm done, I'm deleting/abandoning/whatever."

I think it's only fair to have a little warning.