In computing, a wildcard is used as a placeholder to represent other text, and is often represented with an asterisk (*). For example, if you wanted to find photographs on a system, you might search for “*.jpg”. This search would match files like “birthday.jpg” and “newcar.jpg”, but not “contract.doc”.

In late 2016, over 30 million customers lost phone service in America. Why? Because some poorly written software treated a blank space as a wildcard.