Don't get me wrong, not saying it's all about the tools. Ownership is probably a problem...I'm just saying that I was in many situations where knowledge sharing was lacking/was a problem, but never was in a situation where people were not sharing because they wanted to keep control...doesn't mean it never happens. What I saw however, was lack of incentives, processes, coordination, empowerment, responsibility, culture, and yes lack of tools. People share when their content is consumed. If the only thing you have is an intranet with thousands of folders and files and you don't know if what you share is usefull, it will never become a habbit.