Jack Dorsey, the co-founder of micro social network Twitter, is returning to the company as product lead and executive chairman. Dorsey quit the CEO position in October 2008 to be replaced by cofounder Evan Williams. Some say Dorsey left because Twitter was struggling to meet demand and others because it wasn’t making money. Either way, Williams was replaced in October 2010 by Dick Costolo, who was charged with making the company generate some cash.
Now Williams will be replaced again, stepping back from Twitter on a day to day basis. Dorsey will fill his shoes as lead product manager but will also work on his venture as CEO of Square, which develops a credit card reader the size of a key fob that plugs into the headphone socket of a smartphone, turning the device into an electronic point of sale.
Earlier this month, Twitter celebrated its fifth birthday, now signing up 500,000 new users every day.