It should be noted that Yo has the Snapchat-esque we-cater-to-teens UI and UX that other apps like Tinder and Slingshot have adopted. (bright pastel colors, whimsical fonts, app incredibly unintuitive to navigate due to excessive minimalism, etc.)
I'm beginning to think you could make literally any kind of app with that kind of paradigm and get funding.
Reviews on Play seem to be full of "I only installed this app because <friend> told me about it."
It's actually kind of interesting; you don't really need much of an onboarding flow because either you play with it to figure out how to use it (and apologize for the accidental notifications later) or you are told by a friend and they tell you how to use it.
I'm beginning to think you could make literally any kind of app with that kind of paradigm and get funding.