Odd Job, that depends upon if the thread originator even had thread notification on! It's an option in the user controlpanel as to whether it is the default action.
If it is not your default setting, then you would have to set the notification type for each thread you replied to (it's in the "Reply To Thread" options below the first "submit" button)... Or at least those threads you wanted to be notified of.
Add to this, you cannot tell who is going to be notified and who isn't when you reply!
At any rate, my personal preference is not to resurrect old threads unless there is actually more info relevant to that thread. But that's just me.
Here's what I have seen: Old thread gets revived. New folks don't look at the date of the original poster. Arguement ensues; or irrelevant posts made... Thread gets locked.
So... I didn't "vote" in the poll, as it is not a question that has a black and white answer.