From the other comments on this thread and my tiny bit of Snapchat use, I think you're wrong about Snapchat being in the "promotion [over] communication" bucket

From the other comments on this thread and my tiny bit of Snapchat use, I think you're wrong about Snapchat being in the "promotion [over] communication" bucket. As a largely private, ephemeral communication medium, it seems much worse for promotional purposes than other social networks.