Greg Sterling waxes poetic about the value of query refinement within search verticals.

Couldn't agree more. Semantic (vs. purely statistical) query refinement is a key differentiator for vertical search plays, and one that I'm certainly mindful of as we build our solution.

But I have to disagree with Greg that this is an alternative to user generated content. Knowing that a service provider says that s/he is open from 7AM to 7PM (et al) is critical; knowing that 9 out of 10 reviewers think the service is quick, friendly, helpful, etc addresses a different consumer need entirely.