No account creation, so it's probably just tied to your device - sort of like Yik Yak, I guess. Things seem to be geographically correlated, though I imagine that the more 'viral' a thing is, presumably the further it can spread.
edit: I guess you can create an account, but it's not required to 'infect' crap.
At least here in NYC, it seems like one user is generating 99% of all content. A third of it is "art", a third of it is gifs of girls twerking, and another third is just celebrity snapshots.