I would like to suggest to auto-close threads after a certain period of time. One year or so would be perfectly fine, six months would possibly be good, too.
Should really some new and important information emerge, we could always link to one of the older threads.
But having the option to give some necrophiles the chance to perform in public ... is giving me the creeps.
So, in good "Dawn od the Dead" fashion ...kill it before it turns into a Zombie!