Jeff Oxenford runs into the same trouble that anyone involved in knowledge management runs into: What is knowledge? (and what is knowledge management)
My biggest challenge? Defining my job around the campfire. In explaining it to folks, I became clearer with some things.
Jeff talks about knowledge and knowledge management in terms of the problem to be solved. In his case, it has to do with decision making. In other cases it may be creation of new ideas, or the capability to manage projects.
It's important to revisit this for yourself and your organization from time to time. I am very much in line with Jeff's definition around the idea of "what is it for you" rather than coming to a formal definition that works in all circumstances. My reasoning is that as long as I understand what you need from "knowledge," we can move forward.
That said, I fully understand the need to dive deeper and play with the underpinnings of the terms we use, so that I can be clear in my discussions with people who aren't interested in the depths.