US Federal Bureau of Investigation director James Comey designed his social media presence to be safe from prying eyes. He set up a private Instagram account only followed by family members, and subscribed to Twitter under a false name.
After just one mention in a public speech, it took only a few hours of a reporter's time to discover the accounts with certainty approaching 100%. (Apparently in response to the story, the Twitter account – which quickly started gaining followers – is now available only to subscribers approved by its owner.)