When strolling the streets of an online virtual world that allows user-created content, it is not uncommon to see brands that you recognize. A Ferrari may roll past you in the street. The avatar walking toward you may be cushioning its steps with Nike-Swoosh-emblazoned tennis shoes. The virtual jewelry store that you pass may feature a gleaming Cartier necklace in its window. Familiar brands cushion the virtual experience with the trappings of familiar surroundings for the software user. The problem is, chances are these brand owners never created these virtual goods, and the money from their sale likely went into someone else's pockets.

Within many virtual worlds, users are able to create their own content. A virtual world allows users to live out fantasies that they might never be able to fulfill in real life. So if you were creating a car for yourself, or to sell to others within that world, why not make it a Ferrari or a Lamborghini? When you create a pair of sunglasses, why not decorate them with the Gucci logo to mimic a pair you've admired at the shopping mall in real life? Successful brands attract buyers, and this maxim is no different when the buyer is in the market for virtual goods rather than real ones.

Most users of virtual-world software probably aren't thinking about trademark law when they create virtual knock-offs of successful products. However, the practice potentially raises real-world legal issues.