Most, or at-least some of the best 3D smartphones you can ditch your glasses and still watch the 3D effect on your mobile phone. These smartphones have a layer in front of the screen that allows visualization of Stereographic 3D images. The layer is comprised of parallax barriers, a series of tiny slits that helps each eye to view different sets of pixels.
However, you really have to make sure that you are positioned exactly in front of your phone’s screen for optimal 3D experience. Changing the angle slightly will not just affect the 3D quality but will make the image look a lot blurry causing a bad experience and strain to the eyes at the same time. With this constraint, watching a 1 minute video clip could be an awesome experience but I don’t think that it is easy to maintain the right angle throughout a video clip that lasts for about 5 minutes; and how about watching full length DVD movies – Not possible unless you put the phone on a dock or yourself! That is certainly a downside of the technology.
Moreover, sharing with the next person could well already be a big problem given the very limited viewing angle. If I want to watch a cool video simultaneously with the another person, it is impossible that both of us get the optimal quality; the uncertainty principle with Physics applies here.