Well, where to start. It's magic what they do. A tool to do it all at once: manage the docs, the projects, the notes. A nugget.
☑️ No frills
🛑 Too slow
Internal documentation, by Dropbox. Extremely useful if you already use Dropbox to store your documents.
An internal collaboration tool integrated with Salesforce. The perfect replacement for Google Docs if you use Salesforce.
The ideal internal wiki tool for teamwork. Plus, they're French.
Slab allows you to create a corporate wiki, so that everyone can collaborate intuitively and without losing information.