Read
>>2 and
>>5 before replying to this.
As for my own opinion, I don't think it's necessarily important for organization, but it would be nice for time-restrictive threads like special event missions or convention threads. On the other hand, it's nice being able to go back and read them later on, even if the event is done.
I'm on the edge. I don't know if I'd like the idea or dislike it. I do know that it shouldn't be mandatory to set a timer tho, and I'm not positive how well that kind of system would work on a BBS versus a forum.