Part 1 described the mechanics of an economy based on the unused processing power of desktop and laptop computers on the internet. Part 2 gave a detailed example of a digital media store like iTunes that could use this spare power to offer free music while still compensating the artists fairly. In this part, we'll do a comparison of some popular free Massively-Multiplayer Online (MMO) games between the revenue they earn and how and the revenue they could earn through the spare computer power of their users.