Probably due to the fact people don't like being forced to share everything when all they want to do is read a story. No Yahoo I am not giving you access to my info so I can read a story on your site.
Frictionless sharing is just a bad idea. It's annoying, intrusive and a bad way of discovering good content. When it comes to sharing, Friction=Value, the 'friction' is the filter which just lets through the worthwhile stuff rather than everything.
+Fawad Kazi You can see Facebook in the internet..... Just type in your browser.... www.facebook.com.... It`s kind of a social network... But I think you wouldn`t like it.... it allready saw the top of it`s popularity... ;-)))