Battelle recounts the early development of PageRank -- the inbound link count for a page as a metric of "importance" within the community -- and the subsequent improvements in search results that Google achieved and which has led to Google's success. But perhaps more importantly, he details the thread of ideas and events that led to the "pay per click (PPC)" innovation in the advertising business. PPC accounts for the enormous cash flow into Google and other search engine companies, and can be viewed as a main salvation for the Internet during the post-dot-COM crash of the early 2000s.

The picture, while certainly rosy, is not without flaws. There is a major problem with "gaming the search engines", and Battelle's treatment of the some Search Engine Optimization (SEO) scams is mercyless. Even worse, the general problem of click fraud -- how to weed out [and not be billed for] click-throughs to your site that arise from third parties or competitors -- gets a deservedly scathing attack.

You can read about these and other issues affecting the search industry in John Battelle's Blog, where you'll find a lot of current (December 2005) discussion about the click-fraud issue.

One subject missing in Batelle's book is the issue of validation of search results: how do you determine that a search engine's results really are as unbiased ("objective") as the search engine claims? [Hint: This might be a subject of a later post here!]