"The Internet is littered with abandoned knowledge-sharing portals, so what questions do you need to ask before jumping in and setting up a new one? Kirsty Newman lists four questions to ask before setting up your knowledge sharing one-stop shop."
Comment: this prompted more questions than a simple comment allows me to phrase. In essence, I think what Kirsty says makes a lot of sense, also from the experience we have with setting up and maintaining learning networks. See for further details my blogpost at http://pbsloep.blogspot.com.au/2012/11/about-setting-up-learning-network.html