Show me one place in the entire process that says you can use your existing key without having to repurchase the software. When I bought the software, not once in the purchasing process, or after, was I informed that I would have to install steam then figure out how to transfer my serial key to the Steam site before I could even download my purchase. Its all very well being sarcastic and putting people down by telling them that ' no one requires you to purchase it again for that', as if it should be blindingly obvious to us, but where was that information? At that point, no-one had advised me that I could use my serial number purchased from here, to download the software on steam (a completely different site) so at that point yes, I felt ripped off, and justly so!. If you tell someone that they are buying a mac version of a program and then don't deliver, then yes its a ripoff cause you are not supplying what you advertised.