I'd like to see how all this tech battles motion sickness. Like many people I think, reading while riding in cars/buses gives me motion sickness. This doesn't happen aboard trains.
With an AR windshield, you could put the content in the real world. Instagram posts could show up on fake billboards, or tweets could appear to be written on the road. Then you wouldn't get sick because what your inner ear feels matches visual input, but you could still consume your content.