A recent article at destinationKM.com discusses why more people in an organization don't spend more time sharing the knowledge they have. It suggests that the top five reasons are:

1. People believe that knowledge is power
2. People are insecure about the value of their knowledge
3. People don't trust each other
4. Employees are afraid of negative consequences
5. People work for other people who don't tell what they know

A reason not mentioned in the article but critically important is that an organization can't value people's knowledge without valuing people. A company that doesn't say, 'you are good at your job, we couldn't do what we do without you', and mean it, can't expect its employees to readily share knowledge, trust that knowledge sharing will be positive, or even believe that they have knowledge worth sharing.