In the terms of High risk investment, i think STP is the best place to use except for Forex, which also High risk investment but Paypal accept that business with some conditional terms before Paypal will accept it.HYIPs,Cyclers,Matrixes,MLM etc made STP to be more popular but I noticed that it is just perfect with HYIPs. STP is always having issues with Cyclers/MLM because I can see that in some programs that I invested in,admins of those programs are always removing STP as one of the payment processors that is been used in the program. I don't really like STP because of the high fees.