Yes, it does. Every Yeah you give, every community you join, every comment you make, every drawing you create etc is data. Of course Nintendo measures this data and is able to see what kind of games creates how much traffic. How many comments are positive or negative? How do people react to developer documentarys/comments/insights? How long does a game have an active community? And all this in relation to the sales. There's no way Nintendo doesn't valuate this data statistically, it's pure gold for them. And thus, they can react themselves to trends, likes, opinions, and so on.
Users are very honest on miiverse. If they don't like a game or a certain feature, they put it into the miiverse and soon others will join them. You could argue that nobody would talk badly about something he or she spend money on, but that's not true. There are plenty of negative comments. Just look up the community for Legend of Kay, for instance. Lots of people enjoy that game, but a lot of people mock the camera, myself included.
Miiverse is a good measure of how the crowd likes or dislikes a game, because it sums up the voices of the many. It's basically working like Metacritic.
