How different is it than people just using iMacs with iChat video?

Much higher quality. There is something in our animal selves that demands a certain threshold of realism, which these new systems have. Technically, it's just higher resolution, faster connections, better screens, better cameras, etc., but the total effect is greater than the sum of parts, as in the system replaces plane tickets instead of phone calls.

This article in the economist was good, but now behind a pay-wall: http://www.economist.com/business/displaystory.cfm?story_id=...

A major factor in telepresence immersion is eye-contact. http://www.google.com/search?q=telepresence+eye+contact Perhaps someday a YC company will figure out how to inexpensively enable eye-contact over ordinary video chat (teleconferencing).

That's the half-silvered mirror solution (for full eye-contact teleconferencing). I was thinking of the other solution: the software-based one that corrects the images in terms of pupil-direction.

That could get really creepy, really fast..

It seems to be what HP and Cisco are using for their immersive telepresence systems. I have seen plenty of rave reviews of Halo, and never any complaints.

Will the practicality likely increase over time?