(via Phil Bradley) Inside the Searcher's Mind: It's a Jungle in Here!: "There's No Such Thing as an Average Searcher." A study by a marketing agency, and therefore suspect, but still worth a read.
"For instance, women tended to scan all organic [he means non-sponsored] results and read titles and descriptions more carefully than men."
Mmm...
Other conclusions are about banner blindness ("It seems that people have already mentally divided the results page from their favorite engine into sections"), search behaviour ("A person searches, chooses a result, visits a site, and hopefully converts. In reality, we see the typical search pattern is quite different.").
Nothing you don't know and haven't seen analyzed better.
They do have an interesting section about what Jared Spool calls "the seducible moment". In short (and this is my interpretation of their results): don't pitch products during search, instead help users refine their search towards your product. Again, this is my interpretation - the article talks about the "Anonymity threshold". ("If given the choice between getting information and remaining anonymous and getting the information through registering, people will always choose the former.")