Jack Dorsey, former CEO and co-founder of Twitter, is developing a Bluetooth-based messaging application called Bitchat, which enables communication without internet connectivity, Wi-Fi, or cellular service, using peer-to-peer connections over distances up to 300 meters. The app is currently in the testing phase on TestFlight, which has reached its capacity of 10,000 users. Dorsey has expressed interest in learning about Bluetooth mesh networks and related technologies through this project. The app has sparked discussions about mesh networks and resilient communication, but it has also received mixed reactions, with some users expressing skepticism and concerns about potential misuse.