Social networking is one of the biggest buzzwords in the tech industry today - but what if you could bring all the sharing abilities of a social network site right to your desktop? Microsoft's Social Desktop does allows you to share documents, pictures, ... without having to copy or upload them to another location. To me, the security implications are a little scary, and that would have to be addressed, but what with the push toward the \"cloud,\" I wouldn't be surprised if this eventually became the computing model of the next generation. Read more here:
http://research.microsoft.com/en-us/projects/SocialDesktop/