so you're suggesting that you'll change the subject for the first post in a thread; i.e., one that you've originated?
that would be pretty futile for anything that's not on the first page. and artificial if you were to make old threads current just for that. or have I misread your intent?

(and then the are the "hit and run" threads, which are probably the most likely to take wild diversions -- just because the originator never comes back to steer things aright.)