Hillary Clinton’s email has vanished but why can’t yours?

The warnings about the longevity of email are regular and ominous: Don’t be careless with it. Email is forever.
Indeed, in some very high-profile cases it seems that way. Former CIA director and retired US Army General David Petraeus lost his job and his reputation, and "gained" a criminal record in 2012, when emails from an account he thought was private exposed his mishandling of classified information and an affair with his biographer.
Much more recently – just in the past c