A question about Satellite radio (XM in particular)

Obviously they have some way to know that they are broadcasting to an
individual receiver, else (a) they couldn't sell and send signal to
specific devices who pay and not to others and (b) they can deliver
specific programming (Playboy channel, Opie and Anthony) to specifc
receivers.

But - suppose I listen to 'non-premium' channels - for instance, I
listen to 15 (folk music) on weekends and 7 (70s music) during the
week, and 132 (C-Span) during rush hour. Can XM track that
information to a per-subscriber level? Do they have a way to know,
for instance, that any moment there might be 400,000 people listening
to NASCAR and 1000 to America Left? What's their capability for usage
analysis?

(The reason I ask - I like 15-Folk and I hope that enough people
listen to it to keep it on the air.)

Ted

--
Ted Koppel