But with that kind of money stream behind it, the mouse can go back to his investors and purchase a tiny mouse jetpack (or whatever the SEO equivalent is) to gain an advantage. If the cat learns to swat that, he'll come back with a toy car. Google is fairly active but eventually they give up: the mouse is a lot more motivated to get his cheese than the cat is to get the mouse. Google can penalize them 10 times in a row, but the 11th time, they win - and they essentially have the bankroll for infinite attempts.