Here's the thing: Some of these sites may employ techniques that are plausible for the level of income they claim they generate, but you'd have to have been one of the first hundred or thousand people to spread your referral links and such around the web. Furthermore, they target people who in the very beginning are not going to put in much effort into what they have to offer to feed off of that desperation, hence the earn "easy" money part. My general rule of thumb is, if it looks like a scam, works like a scam, and has little positive reviews or no reviews at all, it probably is a scam.