G. Phillip Cartwright. Your whole implementation must ensure that the answers to your users' questions are in the repository and easy to find. You'll know you're there when your users call you, upset that something they expected to find wasn't there or was hidden. To put it another way, you've achieved success when people put enough faith in the knowledgebase to be let down by it. Focus the material.
People use a knowledgebase because there is some hope that what they are looking for is in it.
For the initial implementation, this means picking a relatively small subject area. With a small subject area, you can build up enough content quickly to make your knowledgebase useful. Make sure your knowledgebase will grow. If adding to the knowledgebase is optional, it won't happen. Users will quickly realize if the information in the knowledgebase lacks real-life content and ignore it.