These items are often used by their owners to send a very specific message.

WSJ: Where True Value Lies

Under newly inaugurated President Park Geun-hye, South Korea's Defense Ministry, which often brushes off North Korean threats, has looked to send a message of strength in response to the latest comments from Pyongyang.

NPR: SKorea, US Begin Drills As NKorea Threatens War

Often when that happens, someone from the company will send a private message to that person.

CNN: Get results by social networking with airlines