Are you f'kn serious? Facebook holds the holy grail of information about what people "like" and are into. Why do you think Google launched Google Plus??? THEY WANT THIS DATA. If Facebook launched an outside ad network they would generate an even more insane cash flow and their stock would soar.
Dude, just because they know what people like doesn't equal a sale. Yes, it's sick as fuck that they know what everyone likes and that data is super valuable, nobody is debating that I don't think unless they're retarded.
However, like Guerilla said, Facebook doesn't have intent. If Facebook knows I like fishing boats, they can throw fishing boat ads at me on the sidebar and I may or may not click out of curiosity.
BUT, if I actually want to BUY a new fishing boat, guess where I'm going to look for one? Google(or some other SE), not Facebook. If Google could get their hands on FB's data about people, it would be pretty sick. But FB doesn't have the means to really exploit that data because they have no intent based service.
At the very least I feel like FB should implement some type of FB homepage that shows a simple search box, and the users email. Then encourage users to set it as their homepage. I mean, Bing sucks shit, but half the people on FB probably can't tell the difference between Bing and Google anyway.
If FB wants to ever think about competing on the level of Google, they better get their fucking search game in order. And I don't mean competing on the level of Google in terms of our parents saying "Oh this FB thing is great, it's the next Google! Let's buy some stock!". I mean REALLY competing on the level of Google in terms of value, revenue, and need. I don't "need" facebook, if facebook died tomorrow my life would go on as normal. If Google died tomorrow I would lose my YouTube account, my email which the the soul of my online life, and I would have to find and use a different and shittier search engine.