What? web-based collaborative outline
Why? Collaborate on an outline to share ideas effectively and produce an artifact. Meetings run more smoothly; Students get better grades.
Who? People in meetings. Students. Planners. Everyone.
How? Create an outline right in your browser. Send your friends the URL and they can work on it with you.
Diff? More natural feel than any browser-based tool you've ever used.
What? A social network for music collaboration, users record their inspiration and share with friends who may contribute adding their own over.
Why? Because capturing music ideas is very easy and fun, no extra gear is required apart from the built in mic in your computer.
Who? For the musicians and for the music lovers, you don't need to be a guitar wizard to enjoy creating and collaborating on music tracks.
thinklinkr 
Thounds What music are you thinking?