Marco Arment lists the ways people use search engines and talks about how spam has taken over each of them. I think his categories of search types are pretty accurate and agree completely that spammers are systematically taking over each of them. I find that going to Amazon or other trusted retailers and looking for reviews is much more useful than looking for product information on Google these days. I also find that I use
site: searches more than I ever have before. Trusting Google to return results for the whole Web just isn’t very effective any more.