Looking for a knowledge base application

Could anybody recommend a decent knowledge base type software application (open source would be prefered). Looking for something that is 'easy' to update and maintain. A coworker in another department attempted using mediawiki, but has proved to be non friendly for others to add or update information. A wiki application would be fine if their is a tag along application that would allow for easy 'cut n' paste' so to speak. thank you for your time Mark

Thanks Binary Snake, Couple of these apps look promising. Mark