this has been proposed before...
there are a few minor complications:
in the users info file, the only dates stored are his last posting date and registration date
users could be 'pruned' by their last posting date, but that would be unfair for "lurkers," who like to read posts but not write them
if it were to be done fairly, the user's last login date would need to be stored too, though that shouldn't be too hard
then you'd be able to 'prune' users who haven't logged in for ages
EDIT:
I took away some smilies... this time I put in too many even for my own liking
[ 01-03-2002 06:25 AM: Message edited by: pumpkin ]