Sharp will start mass producing (read, it is not just a concept) a LCD monitor that can display two images at the same time and only the viewing angle determines which image the viewer is seeing. For instance you could see a PC desktop when looking at this Sharp LCD monitor from the left and a TV image from the right.

I am still trying to get used to the idea. I have a hard time figuring out what this is good for in real life. My thoughts so far are: watching two TV programs at the same time, sliding left and right in front of my desk switching between two virtual desktops, sharing a monitor between two people - all sounds not really practical.
Sharp thinks the dual view LCD monitor has uses in public information displays, as you walk by two different screens are exposed.
The Sharp press-release (Japanese) does not really go into details how technically the Dual view liquid crystal display works.

There are also 3D LCD monitors available from Sharp that, I guess have a underlying similar technology.