Virtual worlds today are walled gardens, their 3-D landscapes divided in much the same way that AOL, Compuserve, and others divvied up the 2-D Internet in the 1990s. Now a group of more than 20 companies, including IBM, Linden Lab, Multiverse, and Forterra Systems, has begun talking about how to link together today's virtual worlds to form a 3-D Internet by establishing a set of common standards. Although there are still many questions about what form that 3-D Internet might take, a major goal will be to make it possible for users to move from one world to another as easily as people today navigate between websites.

"We see this as the next logical step in the growth of the Internet as a whole," says Michael Rowe, manager of 3-D Internet and intraverse (an in-house virtual world) for IBM. Rowe says that today's walled-garden situation hinders the development of the Internet by making it exceedingly difficult to offer virtual goods and services in more than one location. For example, he says, someone who wants to create a virtual storefront in several virtual worlds now has to design and build the store separately for each world, using radically different processes. Standards for a 3-D Internet, on the other hand, might allow the shopkeeper to provide links that people could use to reach the store from any virtual world, in much the same way that people can now use a domain name, such as Amazon.com, to point to popular shopping sites.

To make the virtual-world experience as rich as possible, Rowe says, developers need to find ways to consistently render objects--including avatars, which people use to represent themselves in virtual worlds--across several worlds. For example, he says, someone who has built a car in MTV's Virtual Pimp My Ride might want to take it into Linden Lab's Second Life to show it off. In order for the car to remain the same in both worlds, its underlying programming must make sense to both systems. Adopting 3-D Internet standards, Rowe says, will allow developers to solve these types of problems and open their borders to one another.

But the issue goes deeper than virtual cars and shopping malls. Jaron Lanier, interdisciplinary scholar in residence at the Center for Entrepreneurship and Technology at the University of California, Berkeley, and a virtual-reality pioneer, says that the search for a 3-D Internet is important for humanity. "Human cognition was designed to function in 3-D, and our computation eventually has to have a 3-D interface to maximize the matchup with the human brain as it evolved," he says. People will need to find a way to combine a concrete, 3-D spatial understanding with the connective power of the 2-D Internet, Lanier says.