Probably they were somewhat forced to do it for monetization purposes but it literally died overnight at my university when they started enforcing usernames.
it seems like it might be worth trying to build something similar now?
I'm still surprised no one has retried the Yik Yak strategy (anon, local, snapchat-esque points). I remember how popular it was on uni campuses in my country.
How would you do it differently? Is it possible to have a geolocated, anonymous speech app, or would it just turn into 4chan?