Virtual worlds such as Second Life, have millions of users worldwide. Virtual world "residents" wield huge purchasing power, and use real money in the online economies. Companies as diverse as Adidas, Jean-Paul Gaultier, and MTV have plunged into these unchartered waters to give their brands a virtual presence, using varied strategies.

Virtual worlds such as Second Life, have millions of users worldwide. Virtual world residents wield huge purchasing power, and use real money in the onl ...