Nobody knows if those numbers are BS or not.What matters is what the market participants are told to beleive.
I beleive the service is very convinient for many people and they will pay.
First of all it is not a big money: 40-50 cents a day.
You don't have to take all your collection whenever you go. I , for one, have mood swings and want to hear different music at different time. Burning CDs takes so much time that it is worth to pay 40 cents a day to have access to any music you want.
As for SIRI, they just converted their debt and a lot of big boys got millions of cheap shares. Now they need to sell those shares and if they feel they can make a killing , they will create all kinds of excitement. And if the overall market goes nowhere, people are looking for such story stocks to park their money.
In any case, I think 2-3 mln subs is very acheivable.