If you've ever done any work travel, you know that the people sitting next to you on the plane or in the airport just can't help looking over at your screen to check out what you're working on. Now, if you really wanted, you could go for one of those techie and expensive 3M screen covers that mean you can only ever see your screen from directly straight ahead. Great, unless you're on vacation with the wife and trying to watch a movie or something, or showing colleagues a presentation.
As always, someone's come up with a low tech way to avoid this problem. It could be a life (well career at least) saver.
Source was here