All changes by user must be revertable

There has been at least 2 separate incidents relating to spammers in the last few days. Speaking as someone who is in the process of trying to clean up the mess that has been made, I believe that having an option such as this would be extremely useful. As Ubuntu becomes more popular as time goes by I believe that we may unfortunately see more of this type of abuse.

See this link for the list of changes made by the other recent user that was causing problems:
http://search.gmane.org/?query=&author=Rhett+Trappman&group=gmane.linux.ubuntu.bugs.general&sort=date&DEFAULTOP=and

Note that implementing this would be extremely difficult and would require rewriting large chunks of Launchpad, since currently Launchpad does not keep a reliable transaction log of things users do on the site, only the 'snapshot' results of what they do.

But I believe it would be worth it or we would need to have groups of people fighting spam everyday. This past 2 weeks have brought up 2 separate incidents.

This would be fantastic; separately it would be nice to just hide /remove all comments by a spammer, in one-click; I'm going to file a separate bug about that. This is a lot easier to do because it doesn't require editing a lot of data - just checking the account status when showing things.