Privacy experts have accused the administration of a “fishing expedition” and warned that email addresses can reveal significant amounts of personal information, especially given the huge quantity of data collected by US intelligence agencies. Ben Rapp, chief executive of Securys, a data protection consultancy, said: “Your email address is the most common identifier that you use on the internet. So having your email, your entire collection of email addresses — and most people have more than one — allows somebody to do a fantastic job of profiling you. I think people haven’t really thought about the fact that their email...