Wednesday at Microsoft's annual CEO Summit in Seattle, Gates showed off an even more ambitious technology called TouchWall, which employs a combination of hardware and software to create an easy to use, white board-like touch interface.

"I always like to show something that's new, because that's kind of risky and exciting," said Gates.

Microsoft believes surface computing will be pervasive, and won't be limited to tabletops and walls, Gates said. "Our view is that all surfaces -- horizontal, vertical -- will eventually have an inexpensive screen display capability, and software that sees what you're doing there, so it's completely interactive."

TouchWall is particularly well suited for group situations in which workers need to view flow charts, because it allows everyone to "interact with the information that's there," said Gates.

"You can see how you can train someone to use this pretty quickly and it's kind of a natural extension of Office," said Gates. "And this kind of whiteboard, with a little bit of hardware advancement over the next couple of years, will not be an expensive thing."