‘It’s enough to keep you up at night’ — what happens when a hacker follows a journalist all day and steals all his data?

Just how much data leaks out of a person every day? Perhaps a terabyte, guessed Rapid7’s Tod Beardsley. A terabyte!  Every touch of a cell phone, ever block you drive, every card you swipe – heck, even while you are asleep — firms are constructing a digital mirror image of you.  A long time ago, I called this Your Evil Twin in a book by that name.

Had a lot of fun, and learned a lot, doing this special project for NBC News. Big thanks to Tod, and to Jen Ellis at Rapid7.  Also, as always, it’s fantastic to work with the incomparable video MacGyver Matt Rivera (@MattMRivera), and it was great getting to know Win Rosenfeld (@winrosenfeld) and Rebecca Davis (@RebeccaDavis), who rounded out the film crew.  They even cleaned the coffee pot when they were done, which is both classy and shows an incredible attention to detail. I hope you enjoy it, and maybe it makes you think a little.

(You can also read my accompanying essay here at NBCNews.com)