Telepresence

So, on the way home today i was listening to this interesting podcast of an introductory computer class at Berkeley- IDS 110.  This particular lecture was about telepresence, and I thought it might make for an interesting intro article to the blog.

The lecture discussed the history and philosophy behind telepresence, and instructor Americ Azevedo showed a youtube clip about a CISCO systems project for a high def., suped up, teleconference system with individual monitors and cameras "seated" around a conference table for an interactive, life size telecommunication.  I looked around to find the video and found this one which demonstrates a system with a holographic avatar instead of monitor and camera:

After a little more looking I found an earlier version of teleconferencing:

What is the difference between talking to an image, an avatar or a person?