The company I work at uses wikis to distribute and share knowledge. I always felt when using wikis that they are unstructured, the knowledge is obscured and I cannot even be sure the knowledge I am looking for is even present. Wikis are good for documenting knowledge in case someone on the team forgets something. I would argue that wiki is knowledge sharing backwards. First you document the answer, then somebody has to come along with the right question.
Judging from the meeting I attended where knowledge sharing was discussed the "higher ups" aren't completely happy with the state of knowledge sharing at our company either.
So I suggested using Stack Overflow Enterprise (or a clone) because it is knowledge sharing the right way: somebody asks a question, somebody with the knowledge answers. SO makes finding knowledge extremely easy and it's using gamification to motivate users to share knowledge.
What other advantages might I mention when I go into the meeting to discuss Stack Overflow for our company? Is SO Enterprise used in your company for internal knowledge sharing? What are your experiences? Can you tell me numbers?