I know a lot of you have many people that have registered in the past only to get a link into their signature, their profile, etc.

Here's a handy query to go through all of your users and if they don't have any posts, then it removes their signature and their homepage link:

SQL Query
update ubbt_USER_PROFILE 
set USER_HOMEPAGE='', 
USER_SIGNATURE='',
USER_DEFAULT_SIGNATURE='' 
where USER_TOTAL_POSTS = 0