Does anyone know this? Do the numbers appearing to Miiverse next to games represent actual users and in that sense buyers of a game? Or can they just be fans (but not buyers/oweners) of a game...

Oh thanks...I guess it is then an index of popularity but not actual sales. It would be cool if we could extrapolate the sales...

Yeah, I think that Phineas and Ferb game had FIVE actual owners posting in Miiverse but still had a ton of posts. You can filter so that it shows "users only comments" but users post many times so. There's just no way to get sales value from Miiverse.

Well on the Japanese Pikmin 3 community it shows about 39k users/posters. Yet sales of the game are at about 160k in that region. So its fair to say not everybody posts to Miiverse.