auto-lock for old threads
It seems that old threads are resurrected periodically, which can be annoying. Even though it's common that such threads will be closed by the mods, that of course cannot happen until new posts have been added to the thread which itself can be annoying.
Perhaps a good approach would be for the system to automatically "lock" a thread after a period of inactivity. For the purpose here, it could be where last post date in a thread is >= sysdate-180 days (I hope I got that right). If a thread has been inactive for that long, I see it as a "no harm, no foul" for a poster to start a new thread, with a link to the original if he/she so wishes. This should be a relatively easy thing to implement and can be run periodically with system maintenance. One added benefit is that it would save the moderators the trouble of having to manually intervene.