Many of today's virtual worlds have been influenced by science-fiction writer Neal Stephenson's vision of a Metaverse, described in his novel Snow Crash. Stephenson's Metaverse swallows up the Web and Internet into a 3-D space that users navigate with avatars. But Raph Koster, president of Metaplace, based in San Diego, and former creative lead for the influential game Ultima Online, believes that the Metaverse should look decidedly different.

Metaplace is building a system that's designed to treat virtual worlds like other content on the Web, Koster says. A virtual world, he explains, is simply a place where multiple users can interact with one another or with objects built for that world. Metaplace is designed to allow users to host these places on the Web the way they might host embedded video, and to build them the way they might build other content on the Web.

"We think virtual worlds are just a new medium," Koster says. "That means that like other media--like pictures, audio, and video--virtual worlds are eventually going to start being ubiquitous on all sorts of Web pages."

With Metaplace, designers can build worlds using a markup language, style sheets, modules, and a scripting language. Every world acts like a Web server, Koster says, and every object in a world has a URL. What this means for users of these worlds is that they can move seamlessly from the rest of the Web into the virtual world and back again, he says. A user can browse to any object in a Metaplace world from outside, and every object can be linked to the rest of the Web and exchange information with Web services. With this architecture, Koster says, he plans for users to be able to build worlds with games as simple as a two-dimensional Tetris game, or as complex as the World of Warcraft, a massive, multiplayer, online role-playing game. Users might also build widgets, such as a virtual weatherman who could deliver the latest news from weather.com, or a Coke machine that gives them a real-world coupon whenever they drink a virtual Coke. Koster says that users should be able to stage up a basic world with chat functionality and a map within about five minutes.

Koster envisions users coming to a Metaplace world by clicking on a link in a Web page. That link launches a page where the user finds herself inside a world, perhaps using a default avatar, but no log-in or registration is immediately required. "They don't make you log in to play a YouTube video," Koster points out.

The Metaplace client is basically a Flash application, he says, and, consequently, is available to nearly everyone who uses the Internet. Currently, Metaplace does not allow users to build 3-D worlds, but Koster says that he expects Flash to add 3-D capabilities in the near future. The client will work anywhere on the Web, and Koster adds that he hopes to see user-generated clients built for mobile devices such as iPhones.