Good for XM Canada! Too bad they won't follow suit here in the US. We pay for sat radio so we don't HAVE to hear commercials. Now, they are starting to creep in again. When cable tv was first introduced it was so popular because it was a service we paid for that had no commercials. Now, they are FULL of them (except for the 'premium' channels). Recently while watching the Discovery channel, I timed the commercial time during a 1 hour show and to my surprise, the commercials consumed almost 32 min. of the program!
Let's take a lesson from out northern neighbors and (being the customers) insist XM stay commercial free on all their music stations! We pay for it. We shouldn't be the ones sold to the advertisers!

XM won't be putting commercials on anytime soon (expect this special case where they had no choice). They need to grow their subscriber base as much as possible, and having commercials would halt that and put them out of business, because of their high debt.

The comparison with cable is apt. Eventually they will run out of new subscribers, and then they will start experimenting with ads in order to keep growing the bottom line -- but that's still many years down the road. I'll enjoy it commercial free for as long as it lasts.