We could just put all our personal data on some non-networked machine with minimal software installed. But data like that wouldn't really be much use for anythi

We could just put all our personal data on some non-networked machine with minimal software installed. But data like that wouldn't really be much use for anything. The data is already being shared over the Internet. People just want the data to stay in the right context: financial details shared with a bank shouldn't find its way onto Facebook or a random game company. Using a separate computer for each counterparty would be more secure, but again not very convenient.