According to the Wall Street Journal, Amazon is working on making not one, but two smartphones. And one of them will have some kind of awesome quasi-holographic glasses-free 3D display. That sounds like the kind of 3D people might actually want! The other one is... a phone of some kind. That's literally all the detail that was provided.
The one you're actually interested in, though, did come with a few extra tidbits about this glasses-free holographic voodoo magic.