Bill Slawski who blogs as SEO By the Sea is one of the very best SEO Brains. A frequent posting method of his takes search engine patents or whitepapers and analyses them for insights into the search engine’s algorithms.
His recent post How a Search Engine Might Distinguish Between Queries from Bots and from Humans is typical Bill. Insightful and very useful.
If you’re interested in learning more about how search engines work “under the hood”, then add Bill’s site to your feed reader and follow him on Twitter.