Twitter CEO Jack Dorsey testifies during a remote video hearing held by subcommittees of the U.S. House of Representatives Energy and Commerce Committee on "Social Media's Role in Promoting Extremism and Misinformation" in Washington, March 25, 2021.CNBCBlock CEO Jack Dorsey spent the weekend building Bitchat, a new decentralized, peer-to-peer messaging app that works entirely over Bluetooth mesh networks, with no internet, central servers, phone numbers or emails required.The Twitter co-founder...