A great story about the Linden Massively Multiplayer Online experience
This article is about a non-gaming MMO, Second Life, with a real translation from fantasy money, Lindens, to real $US economy via the GamingOpenMarket.com. Another big difference is the players literally own the virtual property: intellectual (i.e. a game developed inside this world can be sold outside of this world) and virtual (i.e. real-estate and property).

In fact, this article highlights a few of the "money-makers" in this world. The biggest is Anshe Chung, Virtual Real-estate mogul. She has about 24 Million Lindens (~$98kUS) in assets and takes in about 2 Million Lindens (~$8kUS) a month from rentals! (By day, She is a English, German, Chinese teacher in Germany)

To me, it is a world walking a very tenuous line between fun and deep legal gray areas dealing with ownership and currency exchange with a fantasy nation.

UPDATED - 2005-07-01: Is there a Secret Star Chamber-like group in Second Life?