Dorsey will begin overseeing product at Twitter on a day-to-day basis, whilst continuing to operate as CEO of his most recent startup, mobile payment system Square.
Dorsey served as Twitter's first CEO before Evan Williams assumed the post in October 2008. (Williams was later replaced by COO Dick Costolo almost exactly two years later to focus instead on product strategy). At that time, Dorsey took on a less time-intensive role as chairman of the board. Two years later, he launched Square, which allows vendors to more easily process offline credit card payments using their mobile devices and a small credit card reader.
Business Insider first reported last week that Dorsey was in talks to return to Twitter as "something like a chief product officer."
