Don't try to fool Mother Google

From

The Age:Many websites small and large receive over half of their visitors from Google search referrals. And without a sales team to sign advertising deals, most become AdSense affiliates, automatically connecting them with millions of advertisers worldwide.
...
Indeed, a whole industry has spawned with the aim of helping website operators obtain the highest rankings for certain keywords in search engines, and milk the most out of their AdSense accounts.

But small changes to Google's algorithm that determines how high up in search results a site appears can foil any attempts to game the system in a heartbeat. The worst offenders who are caught trying to artificially boost their search ranking are given the "Google death penalty", whereby they're delisted from search results altogether.

So Google can delist if it wants to. Funny that it won't delist, for example, Nazi sites.

And, here's one for Markets in Everything:

Google is tight-lipped about changes to its algorithms, but bloggers have speculated it made the most recent change to crack down on the buying and selling of text links outside the Google AdSense network. Many website operators pay higher ranked sites to link to them, in order to trick Google's computers into thinking the site is more authoritative and thus securing it a higher ranking in search results.