Co-founder Jack Dorsey will take over chief executive duties in the interim as the social network seeks a new leader.

Former Microsoft CEO Steve Ballmer announced today he is stepping down from Microsoft's board.

The game of musical chairs continues at Twitter, where co-founder and former CEO Evan Williams will step down as product development leader, a role that will be taken over by Jack Dorsey, another co-founder who had distanced himself from the company's daily operations.

Evan Williams is handing over Twitter's CEO title to Chief Operating Officer Dick Costolo, as the microblogging company focuses on generating revenue that is consistent with its massive popularity.

Vodafone Group CEO Arun Sarin will step down from the top job at the mobile operator in July, the company said Tuesday.

Skype's co-founder Niklas Zennstrom has handed over his CEO title to become non-executive chairman of the board of directors of this eBay Inc. unit, whose impact on its parent company remains an open question.

Advanced Micro Devices Inc. sales chief Henri Richard will leave the company in September, AMD said Wednesday.