Interesting:
  1) depending on content, as I consider content limitations the weak
     point of Pandora and still haven't figured out how to effectively
     use Last.fm.
  2) portable and free (w/ads it appears).

I'm listening to the 70s channel now via website, ok so far but
not overwhelmed. Gonna give it a week or so. I'm warming to the idea
of the cheap model and free service, no need to save tracks - free
satellite portable radio. I would expect them to add channels and
more device support as (if) it grows.

Urp, first serious downside:

  You have exceeded the skip limit for this station.
  Our basic radio licenses only allow us to skip 6 tracks
  per hour, per station.

So much for the 70s channel... Oh, like Pandora and can choose
an artist and play music in a similar vein. I picked Nick Gilder :)
Ah, much better. I can save as a "preset".

website: http://www.slacker.com/

  - michael, slacker

---- story -----
http://venturebeat.com/2007/03/13/slacker-the-real-ipod-killer/

Slacker is a music player device, but it is also a music delivery service. It is 
path-breaking because it wants to let you take it anywhere: It will be the first 
service to use satellite to deliver music constantly to your device.

Slacker’s service is essentially a personalized Internet radio station, similar 
to popular services Last.fm and Pandora.

[snip]