This is of great interest! My old software had a easy member pruning feature which didn't send them emails, but did allow me to prune (delete) users who have been members for "x" time and with O posts. I suspect many of our 0 post members may have registered only to post a URL on their profile. This is not always SPAM in the usual sense - their URL may relate to the board topics. Still, I don't mind deleting their accounts if they are not taking part in a single discussion.