I agree with Ivan. Apart from a few well-documented and oft-cited examples, the only organizations in which I see KM practiced effectively and well are those in which lives are at risk, and effective KM practice is a demonstrated way of reducing that risk. To wit, the military (e.g., https://en.wikipedia.org/wiki/U.S._Army_Center_for_Army_Lessons_Learned), the Wildland Fire Service (www.wildfirelessons.net), and to some degree the medical community (no recent references).

Business generally is different - no one dies if you get it wrong. Sure, there are pockets in the private sector where this is not the case. In the automotive and airline industries, for instance, correctly solving engineering problems is required to ensure safety. But apart from these examples and others of similar ilk, the stakes are different, and the risk/reward profiles for the decisions that are made quickly become very personal. So in addition to the difficulty of measuring the effectiveness of many KM initiatives, you can add to that the difficulty of getting buy in from leadership and decision makers who may feel threatened by KM (for instance), or who may feel as if KM could undermine their base of power or the political coalitions that they expended great effort to build.