I don't want to be so direct here, but
In this article does anyone have a clue about which company/companies could it be talking about when it says:
I’m not going to out you, but you know who you are?
An interesting aticle that claims Facebook's third largest advertiser is a scam site: http://www.huffingtonpost.com/ Andrew McDermott, Facebook Ads API Partner- Spruce Media:
http://www.quora.com/Who-are-the-largest-Facebook-advertisers TL:DR - Big Auto, P&G
Research CPA(cost per action) adverting. I won't name any names. As profitable as they were, FB ended up suing them. They would go as far as telling people they can get phony "premium facebook status" to get leads and info.
Those companies at a time made up the bulk of FB advertising. Despite being as spammy as pork shoulder and ham, I doubt Facebook would be in existence without them.