From the developer: "The PlimWare SDK allows developers to add strong server based Piracy Protection so only authorized users can run the program, it allows vendors to create trial, demo and retail versions all with the same code base, with PlimWare, your trial period is not affected by users changing the clock or playing with the machine, once a trial period is over, it is over. PlimWare also provides with pay-per-use capabilities as well as subscription based payments. The SDK comes in the form of a DLL or an ActiveX Control. You must create a free account with Plimus in order to activate your software."