As long as you don't revive something as old as
this thread, I think you're ahead of the curve.
(Honestly, it depends a little on the forum and the context. Pre-allo is pretty active, thus a thread that's been dead for 2 weeks is on the older side... but if you have something reasonable to add to the discussion, it may make sense to respond. If your response is just "I agree" or if the thread is more social than anything, then perhaps no.)