I don't know, but I like their payment terms: "mailcash24.com will pay affiliates when their balance reaches the minimum payout rate set by mailcash24.com." Minimum payout is 25K. "Once the member has reached payout they may request payment. Payments will be made within 30 days or a reasonable time after." I can't find anywhere the price of Upgrade membership or the benefits. The link mentioned leads you to a userid/password box: "Uprade members should pay the fee then we can pay you.want to konw details please go to http://mailcash24.com/pages/paidfee.php"