Honest question: What is the battle? Facebook is well within it's right not to sell space on it's website. But what sort of battle do you see Google and Faceb

Honest question: What is the battle? Facebook is well within it's right not to sell space on it's website. But what sort of battle do you see Google and Facebook engaged in? Sure, they both want users to spend time on their websites (which translates into more ads served), but they go about this by offering different services.