You're correct. My friend works for a company that own hundreds of 'adult' dating sites. Basically, these women sit at home and get paid 15p per message they reply to. The men don't realise they're not actually speaking to a genuine woman (not for a while anyway, although some never do). Each message the man receives comes from a different woman (employee) every time.That's why when you ask her to exchange numbers or simply meet up for a coffee she always says that she's 'not ready', 'needs to get to know you better' 'would rather chat on here for a while' etc, etc.
All the while you're paying for expensive credits and it's all going to be for nothing.You think you're chatting to that hot babe in the photo? No. Those photos are stolen from either genuine dating sites (if they're clothed) or from an adult porn site. Bottom line is that if a woman won't exchange numbers/call you/meet for coffee after a a week of messages, it's a scam site.