Stone has kept quite busy since leaving his day-to-day role at Twitter. In 2011, he relaunched the old parent company of Twitter, Obvious, alongside fellow Twitter co-founder Ev Williams and former Twitter product boss Josh Goldman.
Through Obvious, Stone is actively involved with blog platform Medium, motivational app Lift, and conversational platform Branch.
Now, Stone is off to his next project: a mobile-first company called Jelly. Already, Stone has hired four or five employees to work on Jelly, Swisher's sources tell her.