Seconding. This method allows for the easiest discovery old activity, provided(!!) there is a means for distinguishing between thread creators and commenters.
Thoughts: "nina einstein" for a thread creation, and "c: nina einstein" for a comment? Alternately, something like "*: nina einstein" or "!: nina einstein" (although the last one is the system sirenspull uses, and I wouldn't want to shamelessly rip that off. orz) so that the commenters are sorted away from the creators.