At a trade show last year, a PR rep steered me happily toward an IP phone that came equipped with a camera and a display so you could easily have face-to-face conversations over the Internet. I don't remember exactly what the rep said after that -- I was too busy flashing back to the 1964 World's Fair, where AT&T touted its futuristic, just-around-the-corner Picturephone.

I find it fascinating to look back at past predictions of what the future would be -- especially in terms of technology. Sometimes the technology simply doesn't happen (where is my hovercar, anyway?). Sometimes it does happen, but nobody is really interested (if you've got a webcam you can easily set up a VoIP session where you converse with a friend in video -- but do you really want to take up the bandwidth on something that boring?). And sometimes, the technology has arrived, and is in use, but we no longer think it's a big deal.

For example, an article from the December 1900 issue of the Ladies Home Journal (as reprinted by a fascinating blog called Paleo-Future) posits that, in the year 2000, hot and cold air will be turned on from spigots (i.e. central heating and air conditioning); there will be airships maintained as deadly war vessels by all nations; wireless telephones will span the world; automobiles will be the universal mode of transportation; and everyone will walk ten miles a day (well, you can't win 'em all).

You don't necessarily have to go all that far back to find interesting and reasonably accurate predictions of how future technology may change our lives. For example, an article by Myron Berger, in the September 21, 1986 issue of the NY Times, describes how a new device called a "mouse" and the use of pictures on computers (such as the "pull-down menu") could revolutionize the use of computers by allowing neophytes to learn them more easily. "If computers represent the brave new world," Berger wrote, "the simplicity offered by these new products may diminish the amount of bravery many of us need to enter that world."

A lot of technologies and Web sites claim these days to be revolutionary and the lead-in to a glorious and better future. This year alone, I would put Twitter, Microsoft Vista, the iPhone, and various models of Ultra-Mobile PCs into the category of technologies that have been claimed (either by their creators, or by their adherents) to be changing the world.

It would be interesting to see, 50 or 100 years hence, which -- if any -- of these turn out to be the truly revolutionary tech.