Although most people hadn't heard of multitouch until the iPhone's debut last year, Bill Buxton and his colleagues at the University of Toronto were experimenting with multitouch computer technology as early as 1984.

Buxton, now a researcher for Microsoft, says touch technology may be following a path similar to that of the mouse, which was co-invented by Douglas Engelbart in 1965 but did not reach a critical mass until the introduction of Windows 95 some 30 years later. Buxton calls these decades-long ramp-ups the "long nose of innovation," and he says they are surprisingly common.

Touch now may be where the mouse was in about 1983, Buxton says. "People now understand there is something interesting here that's different. But I don't think we yet know what that difference could lead to. Until just one or two years ago there was a real separation between input devices and output devices. A display was a display and a mouse was a mouse."

But now, he says, the idea that a screen can be bidirectional is on the cusp of catching on. "So now not only can my eye see the pixels, but the pixels can see my finger."

Touch anywhere

Although they have not gotten much traction in the marketplace yet, advanced touch technologies from IBM may point a way to the future. In its Everywhere Displays Project, IBM mounts projectors in one or more parts of an ordinary room and projects images of "touch screens" onto ordinary surfaces, such as tables, walls or the floor.

Video cameras capture images of users touching various parts of the surfaces and send that information for interpretation by a computer. The touch screens contain no electronics -- indeed no computer parts at all -- so they can be easily moved and reconfigured.

A variation on that concept has been deployed by a wine store in Germany, says Claudio Pinhanez at IBM Research. The METRO Future Store in Rheinberg has a kiosk that enables customers to get information about the wines the store stocks. But the store's inventory was so vast customers often had trouble finding the particular wine they wanted on the shelf. They often ended up buying a low-margin wine in a nearby bin of sales specials, Pinhanez says.

But now the kiosk contains a "show me" button which, when pressed, shines a spotlight on the floor in front of the chosen item. The spotlighted area is not yet an input device as described above, but it easily could be, Pinhanez says.

IBM is also working on a prototype system for grocery stores that might, for example, illuminate a circle on the floor that asks, "Do you want to take the first steps toward more fiber in your diet?" If the customer touches "yes" with his foot, the system projects footsteps to the appropriate products -- high-fiber cereal, say.

"Then you could make the cereal box itself interactive," Pinhanez says. "You touch it, and the system would project information about that box on a panel above the shelf."

Asked if interactive cereal boxes might be a solution in search of a problem, Pinhanez says, "The point is, with projection and camera technology you can transform any everyday object into a touch screen." He says alternatives that are often discussed -- a store system talks to customers through their handhelds, for example -- are hard to implement because of a lack of standards for the devices.