The definition of 'low-quality' sites can be rather subjective, can't it? I personally get no value out of Mahalo or Squidoo but I know others actually do.
While I might not love eHow's process and tactics, I'll admit that I've benefited from one or two of their easy-to-read articles. (Though I'll often second source that information.)
I think Google's in an interesting pickle to decide whether results should be: fast food or fine dining.
Google could serve up 'fast food' in results (e.g. - farmed content) and it would likely be 'good enough' for MOST people. Plenty of folks will eat fast food even if there is a better alternative down the road.
I'd like to see more fine dining results, but I'm not sure I'm in the majority there. Quality for the early-adopter might look different than quality for the late-majority.
If the algorithm is leveraging user behavior as a signal, doesn't it follow that popular and familiar sites and brands may gain more trust and authority?
Is Google thinking at all about search in this way?