- For well-defined small websites that have good keyword density, AdSense will advertise your competition rather than support for your product.
- Changing your website layout can get your account deleted and forfeit your earnings without warning.
- A website needs to have an established customer/visitor base before incorporating AdSense.
- AdSense alone does not make Google enough money. Investment in AdWords motivates Google (meaning their web spider and META crawler) to work a little harder for AdSense.
Also keep in mind that the majority of the blogs who've been successfully paid have been by dedicated freelancers, businesses advertising specific products, and so on which have dedicated traffic flow. Most of the rip-off stories (which I don't doubt are legit!) have been, as far as I've seen, from personal blogs filled with ranting or LOL FUNNY STUFF spam.
Anyway, read, read, read: