Seriously. This is the one reason I invested in Facebook stock. They are sitting on immense profit potential in the form of contextual advertising.

I would guess it's because the context is relatively obscure whereas with Google it's not.

Yes, they can uniquely identify you by your profile more than Google can, but for many who don't 'like' everything left and right (or like everything they come across) how would you determine what ads to show them? Just because my friends like something doesn't mean I will. And that's a wasted impression.

Google on the other hand knows what you want - you're actively searching for it. It's pretty straightforward for those who want to serve ads to target what they want to target.

I think you're confusing Adsense with Adwords -- Adsense is the offsite platform Google runs; if Facebook told websites using their non-existent off site platform what to advertise to you, that would very quickly turn into a fountain of money

This is why I regularly trade facebook. I easily have made 40% on their stock this year, and this boost is going to knock me over 50%