When I first heard about satellite radio being launched years ago, I thought there was no way the idea would work. I mean, people were going to pay more than $10/month for _radio_? You can get that for free!

Well, I guess that I didn’t count on the ongoing mainstream radio consolidation and format compaction that took any life out of radio that still remained. People clearly had a pent-up desire for diversity in radio.

Today I noticed that XM passed “4 million”:1 subscribers and is well on their way towards their goal of hitting 5.5 million by the end of the year. Add that to Sirius’ goal of 2.7 million subs by year end, and you’ve got a pretty big market — well over a _billion_ a year in revenue between the two by my calculations.

[1(AP reports on XM passing 4 million subs)]http://biz.yahoo.com/ap/050516/xm_subscribers.html?.v=7