The Rice University Neologisms Database

Etymology : Compounding of Instagram, a social media site primarily devoted to sharing pictures, and game. Game has been generalized from meaning a specific kind of competition, such as a sporting event, to any perceived contest, including ones that are not formally recognized and don’t have clear winners or losers. In this case, the “game” is not about a formal competition with rules or winners, but refers to users of the app competing to post the best quality and most popular pictures and thus gaining social status.