The large difficulty with most of these so called 'mega threads' is that the usefulness of most answers is subjective. The reason being that they are opinions. While some may think that 100 people saying the same thing is pointless and spam, another may consider it to be useful as they can understand that it is a common opinion.
I think the real target should not be to stop such threads (because it could actually be a very good discussion), but to further implement measures to reduce the spam.
Every thread can be locked by OP, so i guess that its their duty to lock it down when they get enough answers or when it begins to become spam thread.
This is a good point and I think it's a feature that many probably do not even know is available. I see more veteran users doing this all the time. Perhaps we can somehow make people more aware of this feature?
maybe there should be some kind of penalty for creating threads that already exist, or that are exactly the same like some old ones. People should brows a bit before they make new thread, and some kind of punishment would make them do just that.
What kind of punishment could you have for such a thing? The search feature is really not all too great and so, even if using search you'll often not be able to realise that the thread you started has already been opened.
One thing I have noticed quite a bit is people posting the same thread twice across two different sub-sections of the forum. I personally think that one should be deleted and they should get a warning for this but it could be within the 'rules'. Does anyone know?