@answering service-- AdSense on Facebook apps yields so little revenue because contextual targeting on social networks don't work. Rather, you must target people by who they are.

@Ian-- While the line between spam and good ads and content may be somewhat hard to draw, I don't think anyone will be able to argue with a straight face what is or could be misleading to teenagers that fall for some of these ad tactics and are later enraged. Many of the negative commenters here on this post come from spammers who defend their deceptive practices under the pretense that they are legal. Ethical is a higher standard, as you point out.

Brutal. I'd be afraid of issuing such a challenge, since it's quite likely I'd get hacked-- much more handily!