tedster - 6:09 pm on Oct 27, 2008 (gmt 0)

Good observation, Andy. I have a feeling that sites where H1-H6 structures are used consistently will find that Google trusts this signal a bit more. In other words, Google may be evaluating some kinds of "noise" on a site-by-site basis.

That's just a personal feeling, but it is formed by working with a lot of sites. Those businesses who have the discipline to use H1-H6 correctly also seem to do better altogether in search. It could be just that the business discipline involved extends across many important factors, and the cumulative effect is what I'm noticing.