Facebook does such a good job of ad targeting these days, I've actually disabled adblock on the facebook.com domain. It's weird to be getting ads for products and services I actually want and wouldn't have known about if not for the ad.. there's some junk too, certainly, but overall the ads actually improve Facebook for me. Which feels really weird to say.
I've heard this about Instagram, too, which makes sense I guess since they have the same ad infrastructure. One woman I was talking to the other week said her favorite thing about Instagram was the ads. I was like.. "huh."