The mystery around Google stems from it behaving like an evolving, living breathing organism.
And this organism spins baby.
For years they have spun their positioning algo into a multitude of layers of complexity. Making it impossible for mere humans to get into a top search engine position.
Along comes AdWords (their money Enterprise) and the mystery has continued. They constantly keep their methods shrouded with their eye on profit:
"Automatic Matching automatically extends your campaign's reach by using surplus budget to serve your ads on relevant search queries that are not already triggered by your keyword lists," Google's email reads. "For example, if you sold Adidas shoes on your website, Automatic Matching would automatically crawl your landing page and target your campaigns to queries such as 'shoes,' 'adidas,' 'athletic,' etc., and less obvious ones such as 'slippers' that our system has determined will benefit you and likely lead to a conversion your site."
In other words, Google will automatically take the money an advertiser isn't spending and spend it on searches the advertiser hasn't explicitly approved. For the average advertiser, this is not a good idea....."They're offering you the exciting opportunity to bleed every penny of your budget every day, advertising against keywords that you didn't want to bid on," says Dan Thies an Adwords expert.
It makes sense for Google to keep the animal complex as the profiteers would easily game the system. As an example click arbitrage is a real problem as marketers buy ads on one engine for pennies and send the visitors over to a page with Google Adsense that pays several pennies or dollars more.
This tension between market and Engine,will no doubt stay with us a long time.