@Watermom: moderated (ie, anonymous) users can't edit their posts.

Spammers have been able to enter as moderated users, get a post approved, and then edit that post to contain their spam. The forum does not have any sort of alert on edits, so I can't detect that until a user sees it and contacts me.

@J_Palmer,etc: Regarding photos, we archive them for precisely that reason. The vBulletin attachment system has a history of 'eating' photos at each major upgrade; I've lost all photos 2x now. Over the winter, we mostly move user photos into the PoolForum Picasa account.