I don't really understand why people would go to such a site. Why not just go have an affair on any other dating site? Ones that specifically go to site for an affair ironically don't seem like the type of people you'd even want to date. Baffling.
I think the answer is age old, the excitement of the forbidden. From the picture on their home page, and from all their marketing they promote, sell - the excitement that's missing from one's life.
Movies, fiction....try romance novels, then tell me women, happily boxed into marriage/church/family/soccer, don't vicariously want "more." Look at the preponderance of total sociopaths in our movies that think nothing of fucking around. Who do what the average person can't do(and is too smart to) which is basically anything they want. AM gives them this, or the appearance of it, the fiction of it. Made more exciting by the possibility of carrying through on it.
Seems like that's a pretty darn good "marketing approach," compared to bland and boring "dating sites." "Dates" vs "Affairs..."