An advergame is a game created expressly for promotional purposes. Advergames are usually interactive Flash games or mobile apps designed purely for short-term interaction. As such they are often simplistic distractions, although occasionally an advergame proves to be fun in its own right.
Advergames are often commissioned to support other media, such as game shows, movies or products, with the idea being that more interaction with the property through the form of the game leads to better associations with it. Whether this actually happens or not is an open question, but commissioners often believe that it does.