I don't "get" Snapchat any more than I get Facebook, Twitter, Instagram, etc. etc. These social apps (which are about as social as reality TV is reality) all are more about promotion than communication. In order to get into these apps you need to have a personality that seeks constant attention from others and external validation. The platforms are all about "broadcasting me and tracking the acknowledgement of me", which is great if you're advertising a corporate brand but kind of sad and self-absorbed if you're a person.
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.
