Earlier quoted context omitted.
> "I am not convinced it is that useful to have explicitly targeted audiences for advertisement. It may be better to understand and interpret an ad campaign, but generally, what works best when doing statistical prediction is not what is the most intuitive." If you've collected marketing data that tells you your conversion rate among pet owners is 2% when your conversion rate among the general public is 1%, then you…
Unless it cost your more than twice as much for that advertizing or your showing the same add to the same person several times (ex: hulu). But, the real problem with facebook users is you are far less intrested in adds while on a social website and a lot of clicks are simple mistakes.
Buying an ad on Facebook that happens to be related to something they once had interest in, and may still do, will result in it being shown while they are not always looking to solve a problem or buy a product, but to entertain themselves, and most importantly may not care about that subject at that moment.
Online advertising is not a cut and dry field. You can get great results from either place, but you won't get the same results from both, at least in my experience.