Don't necro threads that haven't been posted in for months.

[crazyates]

Please? It's very annoying.

[Lethn]

What are you going to do then about people who whine for others to search for old posts instead of making duplicate threads?

[niko]

Please? It's very annoying.

How is it annoying? If it was a discussion about something that is still relevant, I see no problem - on the contrary, it is better than fragmenting and duplicating the same discussion over multiple threads.
Another good reason to necro a thread is to check how past predictions and analyses worked out.