Despite the fact that Sony was such a major proponent of 3D this past generation, support for 3D Blu-Ray playback won't be ready to go on PlayStation 4 at launch.
This information was revealed in the console's online user guide, which states that while DVD and Blu-Ray playback will work on day one, support for 3D content won't be ready in time for release. Will support be patched in for PS4 owners eventually? One would certainly expect that to be the case, but Sony has yet to say one way or the other.
It's amazing how quickly Sony has abandoned 3D technology. Just a couple of years ago the company was doing half of its E3 presentation in three dimensions. Remember that? Crazy.