Due to Bitcoins decentralized, open and free nature. More and more scammers are turning to Bitcoin as their preferred payment method. New Ponzi schemes are currently making the rounds in South Africa. The two biggest known HYIP type investment scams at the moment in South Africa are Kipi (MyDeposit241, MyDeposit247) and MMM.
These sites are essentially ponzi schemes, any old investors are getting paid with new investors money, it is essentially a pyramid scheme and it is only a matter of time until they collapse and are no longer able to pay out.
Note: Be-careful when investing in anything that sounds too good to be true. It normally is!