Allo

Google launched Allo on September 21, 2016, because the world's largest advertising company had noticed that people enjoy talking to each other. Edward Snowden called its lack of default encryption "dangerous." Google had said it would store your messages only "transiently." The version that shipped kept all non-incognito messages indefinitely. In exchange you got 563 quadrillion possible selfie stickers and a feature called Whisper Shout that made your text bigger. Google paused development in April 2018 and shut it down in March 2019. It is survived by every other Google chat app, most of which are also dead.