Nintendo has had a pre E3 presentation and has announced a couple pieces of news pertaining to the Wii U:
First of all, some controller changes. The main touchpad controller for the Wii U, the "Wii U Gamepad" has seen a bit of a redesign, with adjusted grips and analog sticks. Start and Select have been put in a more accessible place and the previous 3DS-like analog slider pads are now full fledged analog sticks, clickable like your standard 360/PS3 sticks. The GamePad will have various functions, including a video chat, but it stands to be seen just how effective this will be. A quick video call to a friend playing the same game to invite him to play together online could be an interesting change, but could also get old quite quickly. The GamePad will also function as a TV remote; if you plan on just playing your Wii U, you can now turn the TV on with the GamePad instead of reaching for the TV remote.
On the software front, we have been given a glimpse of the Mii Universe, a vastly expanded version of Wii's Mii Plaza. When you start your system, you'll see group of Miis "conversing" about games and applications. Some games will have the ability to incorporate this into level selects, etc to see what other players think before you even begin to play.
We were also shown a bit of specific social interaction; someone 'posting' about a level in a game and someone seeing this post on his mobile phone. At this stage, I would say this is more proof of concept than the actual system; it could potentially be interesting, especially if Android/iOS apps are released to match. It would be a bit like a private twitter feed amongst your friends and fellow gamers on specifics. Or at least that's one possibility.
Throughout the week, we'll hopefully have more concrete examples and of course, tons of news on upcoming games. Fingers crossed for a bit of info on Smash Bros 4, but that could be a long shot at this point.
Stay tuned, inmates!