IdRatherBeSkiing
Sherbert is NOT and NEVER WILL BE ice cream.
There was some question about how many 'actual listeners' Slacker has. From what the press release says they have 25 Million listeners while 300,000 of those are paying customers (wonder how many of that last number are from the old XM before it became SiriusFM?). You'd figure paying monthly as opposed to yearly would be the more popular option to get more people to pony up. Especially considering what $9.99 gets you.
It was only $3.99 if you did it yearly before. People are not willing to pay for internet radio or pay for the enhancements it gives you.
If you have yearly you can upgrade and they take your remaining balance and apply that to N months of premium. So if you just renewed, you would have 12 * $3.99 credit. They would take that and divide it by $9.99 and give you that many months credit.