how about formally dividing the site into the tiers you're describing? and reward people for answering newbie questions by advancing them to a higher tier, where more difficult questions could be answered by the members who are tired of answering newb questions. newbies would not be allowed beyond the newbie tier until they've received thanks or something from $x newbies, then they'd be granted higher-level access and they could choose not to be bothered by newbie posts anymore. (and so on and so forth, with several, or at least a few, tiers total.)

surely this has been tried before...?