plaintiger: That's an interesting one. I've had piles of fellowship invitations that I didn't want and that said nothing in the message to me, leading me to wonder why I've been invited. I think those messages are somewhat rude in their lack. Some I delete immediately with no response (they hardly deserve it, after all). Others are still pending, even from months ago, just in case I ever decide to join the fellowship. It saves me having to apply. So I am ignoring those ones, but it's because of potential usefulness rather than rudeness. Perhaps there should be a third option: "Take a raincheck"?