Nintendo just announced a major component of its online strategy for the Wii U. Entitled "Miiverse," this online communication system is built directly into the Wii U OS. Even if a specific game doesn't support Miiverse functionality, the system can be activated at any time without terminating play.
Potential functions include video chat, text chat (via both type written and handwritten messages), commenting on other peoples' games with Nico Nico video/Demon's Souls-style on-screen text, and the ability to access a Facebook-like "wall" where you can communicate with others en-mass. All this can be accessed via the Wii U GamePad.
Probably the biggest news is that Miiverse will "eventually" be accessible by 3DS, PC and any device with an Internet browser. Posting messages on your Miiverse wall, having your friends read them on their smart phones, chatting with grandpa about how to scan a zombie's glands, it will all be possible due to Miiverse's focus on "gameplay empathy with players." Weird.
Below is a video of Miiverse's in-game comment system in action via GoNintendo.