The web has always been about content, but in the early days, it was also about understanding the technology that allowed you to publish to the web/intranet. These days the technology is no longer a barrier. We have more tools at our disposal than ever before to help us easily post content; wikis, blogs, discussion forums, etc. are all available at a small cost. Using these tools, anybody in your organization can easily contribute without needing to know html, or go through a gatekeeper. As a result, you might think that intranets are teeming with pertinent, relevant information contributed by those in the know. If that's the case, your experience is very different from mine.
The technology isn't the hard part. Participation, now that's difficult to come by. Look at the Internet email lists you subscribe to. What percentage of the subscriber base actually ever writes a message? I'd be interested in the statistics. I'd guess it to be quite low, maybe 5-10%, and I suppose that a good thing, or we'd be inundated with email, but the flip side is the amount of knowledge out there that is never shared. This trend carries over to other forms of communication, including wikis and blogs. The truth is, understandably, few people are inclined to spend the time to think, write and share. After all, why should they? What's in it for them? Lack of participation extends to intranets as well, and that, more than anything else, is what's hobbled KM.
For that matter, many of us don't do a good job of managing our own knowledge, for our own use, though we'd likely benefit greatly in terms of efficiency if we did so. Personal knowledge management (PKM) is about creating our own knowledge bases and tools to help us do our job's better. From there, the step to sharing what we've collected is just a short hop.
In Steve Barth's article, Self-Organization: Taking a Personal Approach to KM, he discusses the elements of PKM, and mentions that companies are incorporating PKM into their knowledge management strategies. For example, Hill and Knowlton, a public relations company, expects employees to “participate in knowledge sharing for their own reasons first, and the company's reasons second….Hill & Knowlton employees are expected to participate out of enlightened self-interest: to do their jobs more efficiently and effectively…”
Maybe we should promote KM products, first and foremost, as ways for lawyers to find their own information. If they contribute for that reason only, everyone benefits.
Any other ideas? Come on, participate! 
[Article reference spotted on Knowledge Jolt with Jack.] [LawLibTech]