Dani,
I've noticed a pattern where threads are resurrected (often with no added value) after a year and a half, etc. by somebody. It usually follows with Dave S. locking the thread and scolding the user. Maybe there could be a way to auto lock old threads after a certain period of time?
Winbatch
For example:
http://www.daniweb.com/techtalkforums/thread8301.html