Discourse - Discourse is an open source discussion platform built for the next decade of the Internet.
ScribeHow - Create step-by-step user guides, with a simple click
Flarum - Flarum is the next-generation forum software that makes online discussion fun. It's simple, fast, and free.
Fluency - Speak your business, Fluently. Automate SOP, internal guides, and compliance documentation. Centralise your processes, and gain valuable insights into the processes that make up your business.
Simple Machines Forum - Simple Machines offers free open source software such as SMF, the powerful and easy to use community forum written in PHP. Start interesting discussions on your website!
UserGuiding - User onboarding made easy, for less. Create product walkthroughs in a couple of clicks, without breaking the bank.