Affiliate marketing and the search industry are blood relatives.  To understand affiliate marketing, you must understand how and why the search engines, such as Google, work.

Here’s a little glimpse into the world of Google search courtesy of the NY Times…

Mr. Singhal has developed a far more elaborate system for ranking pages, which involves more than 200 types of information, or what Google calls “signals.” PageRank is but one signal. Some signals are on Web pages — like words, links, images and so on. Some are drawn from the history of how pages have changed over time. Some signals are data patterns uncovered in the trillions of searches that Google has handled over the years.

Google Keeps Tweaking Its Search Engine - NYTimes