The story of General David Petraeus’s fall gets stranger by the day, but one especially surprising detail is the rudimentary way he and Paula Broadwell carried on their secret e-mail conversations. The CIA director and his mistress apparently sent messages by creating a Gmail account under a pseudonym, then leaving notes in a draft folder that either one could read.

The method has been used by teenagers and Al Qaeda operatives, and it raises a number of questions — for instance, why the nation’s top spy didn’t know that Gmail accounts are supremely hackable; or that governments often request private data from e-mail companies; or that it’s easy for law enforcement to gain access to stored e-mails; or that an account, no matter whose name is on it, is traceable via the user’s IP address.