There seem to be two types of questions:
1) A quickie (the OP just needs an answer to a specific query, often a homework solution)
2) A truly interesting question with lasting impact.
Many good questions of the second variety, I believe, are lost in the din. They don't even get much chance to be up-voted because of the sheer volume of new ones coming in (of, mostly, the first variety). Most people (myself included) look either for freshly posted questions or an occasional "hot" topic.
Are there good mechanisms, in your opinion, to promote the truly interesting questions?