Just a heads up on some of the sites I have seen today.
I have made a pretty good article on this, pressed submit and then hotukdeals tell me i have to sign in again, deleting my article. Pretty ticked off by that, and im not typing all that again, so ill post a link for you guys to read and scan quickly.
Its a first time for me seeing this so might as well share what I found:http://en.wikipedia.org/wiki/Matrix_scheme
I won't list a site as an example, just in case one of you decide to give it a go.