I had coffee with a KM colleague yesterday, and she suggested that "knowledge management is about missed opportunities." It's an interesting way to phrase the idea behind KM. People see the missed opportunities angle pretty quickly: "if only we knew that then." And the underlying idea behind lessons learned is exactly around this: let's not repeat mistakes we made in the past.
But is it just about "missed opportunities?" People have an intuition that the right form of knowledge management will help them catch the next wave, prevent mistakes, run a project faster, etc. In some sense, the belief is that there are many places throughout the organization where "knowledge" is missing or unavailable or ignored - and that knowledge would help (would have helped) make things go more smoothly.
The big question, I think, is how do we make these opportunities happen? As I talk to more and more clients and other interested parties, the general direction is that KM has to be built into the strategy of the organization. You can't just say, we are now doing KM (via pick-your-flavor method) and expect it to work. KM has to be part of the way the business is run, whether it is part of an explicit strategy statement or it is the way things happen. Patrick Lambe's thinking about knowledge-sharing policies or Shawn Callahan's knowledge-sharing principles go some way toward this goal.
With this in place, you can then start talking about how a specific program fits into the strategy: We are doing mentoring to facilitate greater understanding of how the business operates across divisions. We are installing this (part of the) portal because we believe it will highlight ongoing needs in the business. We are doing before / during / after action reviews in our projects because this knowledge exists in our business, and it will help us to move our projects faster.