It's not a scam, it's MLM (Multi-Level Marketing). MLM relies on people networking to create the distribution chain for consumer goods. Quixtar's particular business model of MLM has past the peak of its life cycle in America. They still make money here, but the bulk of their revenues now come from overseas.
Network marketing has the potential to make you wealthy, but most people fail because they put minimal effort into it. It's not all that different from starting any other business. A lot of people get into network marketing activities because they have gold fever. They also like the travel, the high-energy atmosphere, and the social environment - it makes them feel important. They make an emotional experience out of it, instead of a wealth-building experience. These are the people who fail in business anyway.
Don't think of MLM as good or bad - it is what it is. There are pros and cons. To the poster who said google it and look at all the failures, think of those people like the AFCs who come on here and whine because they can't get a date. You aren't gonna see those complaints with the franchise businesses because 1) not everyone has the capital to start one, whereas anyone can get into MLM, and 2) MLM is much higher risk IF you don't know what you're doing.