I suppose what worries many companies about blogging in the enterprise sphere is the "outward" facing nature of blogs. By this I don't just mean the "publishing to the outside world" perspective, but the relinquishing of central control and structure. Blogs (or K-logs) are a fantastic tool because of their ability to stimulate more free-form and interactive discussions, and create loose groupings of common interest. The more enlightened and Knowledge-management-focused companies out there are doubtless using the reduced "meta" load of blogs to gain these type of advantages (and some are even using project-based wikis etc.), but I know some companies look at blogs as if they would replace their structured approaches, get scared at this and shy away from them. Blogs are neither a panacea nor a disruptive force, just another useful tool in managing, maintaining and distributing knowledge and information.