This wiki was created to everything to do with this company. It is created with DokuWiki and several plugins. I keep it hosted on the web and mirrored to a local computer for development and offline access.
I chose DokuWiki because it open source and has a lot of active plugin development. I used to use MKDocs and keep all of my internal documentation in markdown. The downside of this system was that it was tricky to secure information to host on the web. With DokuWiki I have a full ACL that allows fine grained control over who can see what. This means that each customer can see their confidential information while everyone can see non-confidential information. This works perfectly to maintain both a good resource for my customers and a good portfolio and reference for myself.