Yo app ‘is one-bit communication’
Andreessen says that the Yo app is a form of one-bit communication – a message with no content other than the fact that it exists, such as a police siren, flashing stop light or taxicab roof indicator. He notes that missed calls are another form of one-bit communication and in Bangladesh account for as much as 70% of mobile network traffic at any one time, used as a prearranged signal or code:
https://twitter.com/pmarca/status/479522494345277440