Yahoo has reportedly agreed to buy blogging site Tumblr for $1,1-billion – Yahoo’s biggest purchase in a decade. 
Tumblr was set up six years ago, and has attracted a large audience of young Internet users.
Tumblr members create their own blogs, sharing their thoughts and work. They also use the service to follow other Tumblr blogs and receive updates.
The deal apparently calls for Tumblr founder and CEO David Karp to remain with the company for at least four years, running Tumblr as a unit within Yahoo.