Skype, the popular interphone provider is offering its 136 million registered users the option to share documents and applications. In December Skype gave its fans access to Last.fm, which lets them listen to free personalized radios, while talking online.
Pandora is another social music platform site like Last.fm. They both allow you to share, listen to and build your own customized radio and according to your preferences suggest similar artists. I have to warn you that they are addictive, but definitely worth the try. I personally prefer Pandora.