Slacker Radio is a very-well designed site for web radio. It has a basic freebie version, and then tons of commercial tie-ins: buy a song, sign up for service, etc.
With the free part, you can choose a station, create your own, and skip a few songs. My favorite part is that you can read about the artist under "Options >> Now Playing Views >> Artist Info." Also, I like the pretty pictures.According to its press release, Slacker Radio launched March of 2007 at South by Southwest:
"AUSTIN, Tex. [South by Southwest/SXSW] - March 15, 2007 - Slacker, Inc. today announced the creation of 'Personal Radio,' which enables U.S. consumers to customize their own radio stations and listen to them wherever they happen to be. The Slacker Personal Radio experience is available today in beta for PC streaming at www.slacker.com and later this year on Slacker Portable Radio Players via Wi-Fi and Slacker Satellite Car Kits.
Slacker Basic Radio is advertising funded and will remain free to use on Slacker software and portable Slacker Personal Radio Players, while Slacker Premium Radio will launch later"
There you go. Thanks Wilmar!