Interesting concept.
1000 songs on a "slotradio" card for $39.99, but you can only play the card like a radio. You can skip songs, but otherwise no editing of the playlist. You can't use the songs on any other device.
The player/FM radio costs $99 and includes 1 card.
I suppose it could potentially save you money over XM's canned radio and you "own" the "station" forever.
More competition for HD radio.
http://slotradio.org/Wonder how long before the hackers crack the card.