DocJohn is the one to answer this specific to NT, but as far as I know once registered here, membership at NT remains open, whether or not posts are made.

From my observations, some people prefer to read, rather than post, and as membership opens up more of the site to them than would be if just lurking as a "guest, they join but dont post. so IMO it wouldnt be a good idea for members to be deleted simply for not posting. A better criterion might be whether they logged back in again, but even there I would think it is somewhat arbitrary for site admin to determine whether someone has left, simply because they havent logged in for some time

Cheri