"But the evidence is that the exact opposite happened," says Steven Hacker, president of the Dallas-based International Association for Exhibition Management, an industry trade group. "And, in a way, that's not surprising. The differences are pretty stark. A virtual show is one-dimensional, no matter how sophisticated it is. You can't touch the product, you can't bounce the product, and you can't taste it. That's a problem, especially if it's a food-service trade show."

In fact, the growth of virtual booths has been skewed toward information- and technology-related events like PC Expo/TechXNY; one out of 10 shows, according to figures from Tradeshow Week magazine, still doesn't have a Web site. But virtual booths also have flourished at shows dealing with financial services, healthcare, telecommunications, and biomedicine - all segments where new products don't necessarily need to have their tires kicked on the show floor.

Attendees at PC Expo can access the trade show's Web site, click on the virtual floor (which looks like an ordinary diagram of the Javits Center), and then cruise from booth to booth with a mouse. Each click opens a new exhibit. Visitors can preview new products, use e-mail to set up a meeting on the trade floor, watch streaming video, and listen to audio.

Event officials expect as many as 95 percent of the IT professionals attending to use the feature. It is not limited by technical considerations - it's designed to work with the most basic computers and modems - but by whether exhibitors want to spend the money to put up a virtual booth. Says Andy Sison, TechXNY's marketing manager, "It's designed to pull attention to the booth and to add visibility. This way, exhibitors don't need to have the biggest booth. They can have a smaller one and still attract attention before, during, and after the show."