CNN showed a very interesting idea on election night with "hologram" interview appearances during their election coverage. From my perspective, every hologram technology will have to pass the "Help me Obi-Wan Kenobi" test. Can you see and talk to this image? Does it take up realspace on the floor with the humans around it?
It would appear that CNN's hologram techynology does not pass this test. It merely renders a 3-D image into the video stream; Wolf Blitzer does not see a reporter's image standing before him in the studio.
Digging through the gizmodo "how it works post" here, I came across a video for the Cisco on-stage telepresence technology. The demo with CEO John Chambers shows a much closer version- no tricking the camera, just projecting someone's presence into a room., and here in a demo with King of Saudia Arabiademo for the King of Saudi Arabia.
Very cool stuff from Cisco. I don;t know yet how it works or whether it truly passes the Obi-Wan Kenobi test, but it looks closer than CNN's approach.