I've used a WordPress blog and a Screwturn Wiki (at two separate jobs) to store private, company-specific KB info, but I'm looking for something that was created to be a knowledge base. Specifically, I'd like to see:
- Free/low cost
- Simple method for users to subscribe to KB (or just sections) to get updates
- Ability to do page versioning/audit changes
- Limit access to certain pages for certain users
- Very simple method of posting/editing articles
- Very simple method of adding images to articles
- Excellent (fast, accurate) searching abilities
- Ability to rate and comment on articles
I liked using the Wordpress blog because it allowed me to use Live Writer to add/edit articles and images, but it didn't have page versioning (that I could see).
I like using Screwturn wiki because of it's ability to track article versions, and I like it's clean look, but some non-technical people balk at the input and editing.