I find the most effective way to search is to already know where the most knowledgeable people gather around a specific topic and use google to search those sites specifically. I will often search within the context of content aggregators like hacker news, reddit, stackexchange, and other various forums before I rely on a naked Google search but it's a kludge at best and not something less tech savvy people are going to know how to do. And if I'm completely new to a topic it's often a chore just to even find the place where the experts actually hang out.
I think the approach that Stackexchange is taking is going to be far more valuable in terms of search over the long run than Google. Time should be spent on figuring out how to reward domain knowledge experts and making sure they stay untainted and motivated to share their knowledge rather than tweaking a search algorithm in an endless cat-and-mouse game played with content farms.