Pay TV. (Media on media).
Would you believe real commercials on public television channels?
It's all part of an agreement to allow public broadcasters to come
up with the money to buy digital transmission equipment. The plan comes
with a set of rules: The commercials must run only on a digital channel;
stations must still provide a commercial-free channel; and the spots
must run on the digital frequencies, and they can use some of the
channels in their digital frequencies for commercial services like data
transmission. (Electronic Media 10/15)