Alternative Massively Multiplayer Revenue Models

RPGVault has put together a three-page article called "Alternative Massively Multiplayer Revenue Models", in which they offer commentary from several game developers about different methods to pay for an MMORPG's development. Here's an excerpt from Project Entropia's Marco Behrmann:
Project Entropia has a unique business model. Project Entropia is free to download, install and use, and has no subscription fees whatsoever. Instead, we have a virtual economy within the virtual universe. This is based around a virtual currency, the Project Entropia Dollar, or PED. The PED has a fixed exchange rate to the US dollar, with $1 US equal to 10 PED. This means that all in-game trading is done with items and currency that have a real world dollar value.

Another unique concept is that a Project Entropia participant may exchange back virtual currency into real life funds, meaning they can make money playing. Other MMORPG developers often forbid the trade of virtual items between avatars using real money - we do the opposite and support it instead. One might say that we built the functions PayPal and Ebay supplies for other MMOGs into our system.