But both the new tool and Electric Sheep's bots are dependent on tags labeling objects and places; there is no virtual-world search technology that can recognize objects without those clues. Constable notes that, when items aren't tagged, the best his bots can come up with is "object." "We can find them, we can see them, but we can't make sense of them," he says. Dzwigalski says that, while the new Linden Lab search tool filters out the useless list of "objects," it's no better at identifying them. As a result, residents are responsible for tagging items that they want indexed. Constable says that his company hopes to add tools that will let people label their items more descriptively and effectively. "People are looking for a very wide range of experiences and things, and it adds some complexity to the search problem," he says. He points out that people need to be able to specify whether, for example, they want to buy a virtual replica of the Eiffel Tower or visit a virtual reconstruction of it.

But the search problem has consequences beyond whether or not users can shop efficiently within a single world. As developers work to let users pass easily from one virtual world to another, the problem of searching those worlds is becoming more important. (See "Moving Freely between Virtual Worlds.") "This is the same sort of thing that we dealt with in the early days of the Web," says Corey Bridges, cofounder and executive producer of Multiverse, a platform for virtual worlds. "If we're enabling a whole network of virtual worlds, it's critical for the user to find just the world that he or she wants. Odds are, it's going to end up like the Web, where there's a whole bunch of stuff out there, and you don't want 98 percent of it."

Although Linden Lab's tool represents an improvement, it is far from solving the problem. "Search is important, but I personally don't know of any answer in that space yet," says Michael Rowe, manager of 3-D Internet and "intraverse" research at IBM. "I would say search [in virtual worlds] is going to be pretty exciting as it matures, since you're not only looking for a link: you're looking for a thing within a context of space and time."