Nintendo has traditionally been the most closed off of the big three. While Microsoft has opened up Xbox Live to iOS, and Sony has a games platform for Android devices, Nintendo has avoided broadening its reach outside of its proprietary hardware. At E3, however, the company announced plans to open up Miiverse--its upcoming social network--beyond Wii U.

You'll be able to access Miiverse from the web on PC and mobile phones. However, you'll be able to do much more than look at status updates. You'll even be able to purchase games and queue them up for delivery while your system is on standby.

"Our goal is that, in the future, you will also be able to purchase games found in the Miiverse from that smartphone or tablet device and, by the time you arrive home, that game will already have arrived on your Wii U system through SpotPass," Nintendo president Satoru Iwata explained at an investors Q&A.

Like 3DS, Wii U will support games both at retail and via digital delivery. And while Miiverse on mobile devices may not be available at launch, "games in the digital format will be available from the launch time," Iwata said. "For the Wii U hardware system, from the beginning, we've planned to make it possible for people to release their games as either an optical disc or as digital content... There are no technical restrictions."