I would say most of the time when they just post an IM address is for this type of scam. If their only point of contact is an IM I keep on looking. I might try to have a conversation but the moment they mention a cam site you know it's a scam. It's fairly common and I see more of those a day. Someone just creates an account on the site and tries to make cash off the referral system by scamming people to sign-up with their ID. Sadly these sites know this goes on but don't do anything to stop this abuse of their referral system.