A one-bit message is a type of communication that has no personalized or specified content, and as such transmits only a single binary bit of information. It signals an intent and a thought, but does not specify what it is. Marc Andreessen describes "one-bit communication" as having no content other than that it exists.[1] Examples of one-bit messages in the real world include the sound of a car horn, a police siren,[1] and an "open" sign on a retail store.[1] Telephone calls which are deliberately terminated before being answered are also an example of one-bit communication.