Channel drift, also called network decay, is when a television channel moves away from its original shows to get a new audience, or to get higher ratings. It often involves a move from shows aimed at viewers that know a lot about the channel's subject to shows aimed at a wider audience. Most examples of channel drift have a channel add infotainment or reality shows to their schedule.
A well-known example of channel drift is MTV. When it started in 1981, MTV was a channel that showed music videos. In the 1990s, it started adding entertainment and reality shows aimed at a young adult audience. This was the start of a move towards the channel's current focus on shows aimed at adolescents and young adults.