Microsoft has a project team developing a SharePoint plug-in that they refer to as Knowledge Network. The project is focused on taking "what you know" – for example specific job skills or industry knowledge – and combining it with "who you know" – specifically your social network – to create a real time representation of your personal Knowledge Network that is controllable and shareable by you the user.
Check out the Microsoft Channel 9 clip here to get an overview of the product by team leads John Hand and Glen Anderson.
While I like the concept of blending what + who, the implementation does not strike me as very intuitive or user centric. It seems to me the key to capturing and delivering the value of a user’s knowledge network should include making the user experience simple and easy to use. Maybe that comes in the next release.