Sparrow

Sparrow went on sale in the Mac App Store on February 9, 2011 and was the top paid and top grossing app in under a day. People paid money for an email client. That is how good it was. On July 20, 2012, four months after the iPhone version shipped, Google bought the company, moved the team to Gmail and ended development except for critical bug fixes. Boing Boing made a satirical video telling users to prepare by deleting it. In 2014 Google released Inbox, an app with similar functionality. Google shut that down in 2019. The bird died twice.