Robert_Charlton - 9:45 pm on Mar 6, 2010 (gmt 0)
Re h1 headings... I've assumed for years that enclosing arbitrary text in <h1> tags won't in any way boost the page for that text.
I still hold on to the thought, though, that in the context of well-structured, well-linked page, the presence of a relevant text heading will help the rankings of that page. It may not be necessary in this scenario that the heading needs to be tagged as an <h1>. Google might have something akin to a "quirks mode" (but for search rather than for browser rendition) which figures out what your headings are, based on other markup or context.
Some tests discussed at PubCon suggested that there was no evidence that the <h1> tag helped, but I don't know how well-structured the pages in those tests were.
I continue to use the traditional <h1>, <h2> etc HTML structure, to give Google (and the other engines) every clue I can about the meaning of a page, and to give myself a format in which to work. I think that Google's algo in many ways tries to reflect human perception, and HTML heading structure and accompanying page organization roughly parallel how people perceive a page of text visually and cognitively.