One critical feature of most first generation knowledge management efforts is that they were designed and implemented following the standard corporate approach of top down, centralized, resource planning and implementation. In an industrial environment you can maybe get away with planning processes that treat all resources as fungible. Then centralized processes might be adequate, although you would think that the failure of Soviet style centralized economies would give more corporations pause.
Knowledge work, on the other hand, depends on extracting maximum advantage out of the unique characteristics and experiences of each knowledge worker. Knowledge management, from this perspective, has to be a decentralized, grassroots, activity. If you accept that premise, the promise of weblogs in knowledge management becomes clearer. Weblogs operate on grassroots assumptions by design.