Further looking into them, it appear that most of their traffic comes direct or from social media, with the overwhelming bulk of the social being facebook. My assumption is that they are using organic reach from fans and probably more importantly shares.
Anyway, the model seems fairly simple and being a large mailer...my my legacy database for the last 3 years is in the billions (all 3rd party / can-spam compliant) and I have built some very custom tools - one which, I can pull from the data, just facebook users. So I'm thinking of launching a similar site and that overtime, I will have little problems driving cost effective traffic to it, that will get it off the ground.
My only concern is that since I'm not currently in the business, what might I be missing / pitfalls? So if anyone knows anything in-depth about this business model, please chime in.