I once saw Philips technology at the Amsterdam RAI that was intended for several viewers. A type of screen full of lenses that emit different pixels at all kinds of angles, so from this angle you get a different set of pixels than you do from another angle. The drawback is that this is not stepless, and can be compared to a lenticular print (you know, those pictures that look different from the left than from the right) and you can still sit in the “wrong” place if you’re just between two corners, and have some kind of tear in the image. Those tears see beyond “tears” when you move around the TV yourself.
Obviously the technology is in its infancy, but that was about 15 to 20 years ago.

3D technology only works for one person if they’re sitting right in front of them… Well, I think it’s better to go virtual, well, have something like that on your head.

I wonder if these types of technologies will be popular enough among the average consumer. They’re perfect for gaming, making them suitable for 3D displays is relatively simple, but as we’ve seen with stereoscopic 3D, media range is extremely important, otherwise they’ll never take off. Aside from Avatar and some Pixar animated films, it’s (imo) not worth it, and that would definitely be a bottleneck for technology like this.