As Davenport and Prusak state in Working Knowledge: "People rarely give away valuable possessions, including knowledge, without expecting something in return."
First generation knowledge systems expected people to contribute to them because it was for the collective good. Everyone had the benefit of this good work product, organized in the central taxonomy of the firm.
Many companies offered incentives, like gift cards, for contributing to the system. If you have to give away a prize to motivate people to contribute, then perhaps they do not seen enough value in contributing. What in it for me? Sure, you get the Starbucks giftcard. And you get some smug satisfaction for contributing into the central knowledge system vault.
The failure of these first generation knowledge management systems was that the central knowledge system does give the user a significantly better way to manage their personal knowledge. It is outside of their normal workflow and outside of the places they normally look for knowledge and advice. The contribution helps others find the contributor's work product, but it does not make it easier for the contributor to find and manage their own work product.
Knowledge management solutions will work better if they are focused on improving the normal workflow and better capturing that information. The user is more likely to use a new tool if it is easy to use and provides more functionality than what they currently use. As Dion Hincliffe pointed out, the new tool needs to be many times more useful than the current tool for people to use the new tool.
A case in point is a document management system. The system needs to provide much more functionality than the user would get from saving the documents to their local computer. Our Interwoven document management system offers version control, better searching, automatic backup, and many other features you do not get on you desktop. In exchange, as part of the knowledge market the rest of the firm gets the ability to find and reuse those documents.