Google vs. Facebook

Just listening on the radio today a caller calls into a business program to discuss Facebook's falling stock price and makes an incredibly astute point.  He said, when people use Google, they look up commercial services - restaurants, clothes, stuff they want to purchase - which is why Google can successfully advertise.  On Facebook, users go to "hang out" and see what their friends are up to.  They do not go to Facebook to spend money or make purchases, which is why advertising will always feel like an encroachment on the users and will never be successful.

Smartest thing I've ever heard said about Google and Facebook.