I'm using Pete's great way of creating Drupal users by adding a tag, but was wondering (as Michael McAndrew did in the comments on that page) how a different username could be auto-created, e.g. email address or even firstnamelastname. (Presumably the Rule would fail if a duplicate username occurred?)
And bonus question: on the same page Coleman mentioned potentially using Rules to remove the tag and clean up, but I can't work out which action this would be under. Any pointers?