Automatically delete user accounts that have not had any posts in X number of days. This would help keep spam accounts from filling up the db.
If a user has at least one post, then their account would not be auto-deleted. It would only apply to new account registrations that do not post.
Admin only can change configuration for auto-deleting accounts.
Ability to define how many days before a 0 post account gets delete. Admin might want to set it at 7 days, 15 days or 30 days for example.