We need to add support for "deleting" user accounts. However, given that we need to keep track of a users' contributions even after they are "deleted" we never actually delete the account, we just rename it. The "delete" process should:
1. Rename the user to "Deleted User #<editor row id>".
2. Clear out bio, passwd, email.
3. Remove the user's subscriptions, collections, tags and ratings.
Then, on a users' "Edit Profile" page, remove this text: "If you would like to delete your account, please see the FAQ entry: How do I delete my account?" and add a "delete account" link. When the user clicks on this link, the user will need to confirm the account delete and show a "ALL YOUR SHIT WILL BE DELETED" message. (or something more user friendly. )
When the user confirms the account deletion, log the user out and rename the account as specified above. And tell 'em we're sorry they decided to leave.
Also, a couple of other things should be done to round this out:
1. the http://musicbrainz.org/admin/user/adjust-flags/<user> page should change the tab name to "admin" and add a "delete user" button to this page. Maybe the entire template should just be called admin, that would be fine.
2. Ensure that users with blank passwords cannot log in.