Guruger came up with a social networking idea of your music library along with a player for listening. How it works? Well it requires you to download a piece of software (1.5MB) which actually index your music collection and upload the index online at your profile. It’s required to leave the Guruger music indexer open or running if you let others to listen to your music and playlists. Yes i know it might remind you about the social music revolution last.fm, they have a popular audio scrobber engine which tracks and indexes almost all media players.

kSolo.com is dedicated to providing you with the ultimate online karaoke singing experience. The site is the first Web based sing along application to allow users to sing, record, and playback personalized renditions of their favorite songs.
Using state of the art streaming and recording technology, the site presents the highest audio and recording quality with [...]

Previously mentioned goowy has been updated with new features. Well if you don't know yet what goowy is all about then here it is -
What is Goowy?

Manage your personal communications including advanced email, contacts, calendar, and integrated instant messaging (Just Released 2GB for free) all from one place anytime, anywhere.
Organize your digital content [...]