"***** NOTE: This post is valid for the Developer Preview of WinRT and MAY change in later releases *****
Window 8 has enabled developers to hook into various system ‘Contracts’ such as Search, Sharing and Settings. Contracts are like agreements between Windows and one or more Metro style apps, called contract participants, to support some kind of user interaction. There is a contract for each type of interaction, like playing music from an application to a connected stereo, and the contract specifies the types of capabilities the participant has.
In this post we will take a look at how to setup your WinRT/Metro application to be a Share Target. This means that you are allowing your applications to consume data from other applications, this is pretty cool.
I thought this a great article on implementing the new Sharing feature coming in Win8/WinRT/Metro in our apps.