I have never posted anything on Miiverse but this looks like the time to start. Imagine the Disney art that will be posted on there, very exciting.
And to anyone who doesn't know what it is: Miiverse is the social media aspect on the Wii U console. It is similar in feel to twitter but you do not get your own profile and can only post in Nintendo established topics that are set up for each game. It is about the only thing it has over it's rivals, so far.
Here's a link to the website:
https://miiverse.nintendo.net/EDIT: Also it is only available to view in the Americas Miiverse. Hopefully it gets added to the Europe Miiverse when the eShop updates today.