Before you start thinking how to corral information online think about how these people are grouped in real life. Are some of your co-workers your friends? Are there interesting pieces of your personal life that you would want to share with your professional contacts? (The answers should be yes if not, you need a more interesting personal life or a different job.)
Alin Wagner-Lahmy has nice article on this at the Official Blog of Martindale-Hubbell: CES Day 5: The Personal and the Professional.
Sharing professional and social info with one’s professional and social connections gives a better way to broadcast your message to many people, and strengthen your online presence and relationships, and it also gives a more holistic view of a person and allows a much more interesting and fun way to communicate with your friends, colleagues, etc – a connection between two or more people is much more stronger when they share a personal experience, interest or emotion.Anything you put online is potentially discoverable by anyone from any aspect of your life. If you are broadcasting information think about the channel of your communication. Think about the audience in the different social internet sites. You will inevitably have very different groups of information in those sites.
The same holds true for knowledge management. You want to put the information that is most interesting and relevant to a particular group in a place where that group can see it. You filter the content and organize the content depending on the expected audience.