It was explained to me as follows: It includes up to four receivers (including the initial receiver). In other words, I only have one receiver, but could activate up to three more as a "lifetime" subscriber. I'm thinking about taking it up -- as I love the service -- but I've just started using the SIRIUS Stratus and know nothing about the life of a receiver, etc. Still, at $12.99 / month, in two-and-a-half years, it'd be paid for. And when you could three additional receivers to that, I think it'd last WAY over that length of time.
Cade