Cory Webb just launched a wonderful idea implemented well: http://resources.howtojoomla.net/

HowToJoomla! Resources uses a custom Google search to only search relevant Joomla! sites with your keywords.  This isn't rocket science, it's just a really good idea that someone should have come up with long ago.  Cory is well known and respected in the Joomla! community, so I think this just might stick.