Often, "virtual channels" are implemented in digital television, helping users to find a desired channel easily, or easing the transition from analogue to digital broadcasting in general. The practice of assigning virtual channels is most common in those parts of the world where TV stations were colloquially named after the RF channel they were transmitting on ("channel 6 Springfield"), as it was common in North America during the analogue TV era. In other parts of the world, such as Europe, virtual channels are rarely used or needed, as TV stations there identify themselves by name, not by RF channel or callsign.