Sometimes users manage to perform a large number of harmful actions before they are brought to the attention of a moderator. This might be a user rage-quitting and vandalizing his own posts, or a user posting a comment advertising his Area 51 proposal on every semi-related post he can find.
Reverting such series of actions is annoying for mods, as you have to open every item and perform the action there. Moderators can also run into the Captcha for moderator actions, which exacerbates the problem. It would be far easier if something like this could be done from the activity tab of the user profile itself.
Ideally, it would allow for quick actions on many items at once. For example, allow to select an arbitrary number of items from the activity tab an support shortcuts like Ctrl and Shift to allow for quick selection of multiple items. A moderator could then perform the appropriate action on all items at once, e.g. deleting posts or comments and rolling back edits.
There's of course a larger potential for abuse or error when acting on many items at once, so it would probably be necessary to have an easy way to undo these actions.