Great! +1!! (:-)
In the end, you are using the function qa_db_user_delete (in db/users.php) that deletes everything the user has done, but the messages he sent. How about if this is an important user with very important posts? Could make any sense to remove only his name and email and other personal data to create a fake user in his/her place? Does anyone knows how stackoverflow works? Maybe this could be stressed in "Terms of service" before. WHat should be the sensible data to be removed in this case?