How about a filter/option when you create a post?

[Viia]

I create a post in the warlock forums, or the 2v2 forums, or the whatever forums.

I tag it 'priest/warlock' by clicking on radials or a dropdown, or something, so the search function could include 'search combos', click on two little radials (priest/warlock) and pull up all of the posts that are tagged priest/warlock.

Just an idea. I find x/x threads in the wrong place all of the time, that contain very helpful information. Would be cool to just search "druid/warrior" and have all of the posts tagged "druid/warrior" pull up from the druid forums, the warrior forums, the comp forums, and the bracket forums.

[Tyveris]

Hmm, something like that might be doable, but it would be impossible to go back in history and tag older posts. Plus a lot of people might not do it.

Maybe if there was a way to allow anyone to tag posts instead of just the creator, it might work better?

[Alphatier]

This is definitely a good idea.
I also thought about having some topics put into a top-topic section, which would be threads that we truly feel discuss a problem in full length and are especially helpful.
It would take some time to search through old topics, but maybe if a small group of people is given the right to tag threads (both for the suggestion above and the top-topic thingy), it would be possible.