Just been released - go grab it from the shop now and start voting
I've only just got it..but from what I can tell its like a giant survey system..where you answer some questions and can see the results ordered by certain demographics or other criteria.
Not the most useful thing in the world but good to see nintendo are keeping up the free content
edit: had a bit of a play now..when you start it you choose a mii to represent yourself, and then see a screen with 3 questions displayed, and some options - "suggest a question" and "see voter results". To vote on a question, select it and then you are taken to a screen with your mii on a giant circle - to vote you just pick him/her up and drag them to the side you want. Your vote is then cast, and you are given the chance to predict what most people will vote for. After a poll has closed you get personalised feedback, which tells you how many predictions you got right, and how similar your results are to others in the world/your area.
There are also worldwide polls in addition to local ones, and you can submit your own questions if you like..an interesting diversion for now...but i wonder what else nintendo will come up with..