So far, Nintendo's second-screen efforts seem much more limited than Microsoft's or Sony's. The company designed the Wii U around having multiple screens, but the whole experience is very locked in to Nintendo's suite of software and hardware.
Monster Hunter 3 Ultimate is a good example of this: You can connect multiple Nintendo 3DS systems (each running its own copy of the game) to a Wii U (which also needs to be running a copy of Monster Hunter) and hunt monsters together with a local group of friends. The entire process isn't all that elegant compared to Microsoft's alternative, which only requires you to run a free app on your smartphone or tablet--something many people already have. Nintendo has said in the past that it plans to bring its Miiverse social network to smartphones and PCs by May of this year, hopefully indicating that the company is taking a more relaxed approach to the types of devices accessing its content.
Whether these second screen initiatives fly or fail will be entirely up to consumers. So far, most second screen efforts have felt superfluous, though it looks like there's still a lot that game developers can do in order to better tie them into our gaming experience.
Sign up for CIO Asia eNewsletters.