One of the abundant questions left after Nintendo's oddly empty Wii U announcement was the format. Pictures of the console released after the show clearly show an optical disc drive, and we now know the Wii U will use a proprietary 25GB disc format for its games. That's half the size of a dual-layer Blu-ray, and a significant boost from the 8 or so GB on a typical DVD.
As for movies, it actually doesn't matter. Wii U won't support Blu-ray or DVD. Following in the path of the domestic Gamecube and Wii, the Wii U disc format shuns conventions, almost certainly over piracy concerns, and leaves home video of the physical variety out in the cold. That's not to say the console wouldn't support streaming services, the Wii already pushing Netflix, so it's a kinda/sorta lock the service will return (and in HD) on the Wii U. With a growing slate of streaming services and from a variety of companies, DVD playback isn't what it once was.
What does this decision mean? Nothing, really. Nintendo has already shown the lack of DVD playback is a benefit to them, ditching the licensing fees associated with producing hardware capable of movie sources. The cost of Blu-ray in fees alone is around $9 per unit, not much when you're considering one console, more than you'll likely ever see in a lifetime when you're shipping 86 million units worldwide like the Wii. Customers certainly don't seem bothered by it, and since Nintendo president Saturo Iwata has already stated the Wii U "won't be cheap," that $9 per unit is worth more than you probably think.