The Sakai community has several sources of documentation. Our primary source of documentation is held in Confluence and is refered to as the Sakai Wiki

Teaching and Learning Community
The Apereo Teaching and Learning Community is a great resource for institutions with questions about exploring Sakai. Institutions and faculty share their experiences and can answer non-technical questions about the Sakai Project.

Sakai Online Help Documentation
Beginning with the Sakai 10 release, the Documentation Working Group implemented a new collaborative authoring process for Sakai Online Help. The Sakai 10 Help was completely re-written for improved accuracy and better usability. 
To subscribe to the Documentation Working Group email list for news and announcements, send a message to sakai-docs+subscribe@apereo.org.

Google Groups and Mail Lists
The community primarily communicates via Google Groups (Sakai Email Lists). You can find a current list of all of the group discussions on the Sakai Wiki. 

Programmer's Cafe
The goal of the Programmer's Cafe is to produce sets of development documentation and sample code to facilitate Sakai tool development. The idea is to allow a programmer with basic knowledge of Java to go through these tutorials and end up equipped to write a Sakai tool. This is an excellent place for technical staff interested in learning more about Sakai's flexibility and the power of our developer community.

GitHub
The developer community is using GitHub for Sakai 11 and later versions. Sakai 11 is currently under development.

Slack
We currently have Slack groups for Sakai developers, Sakai Morpheus (responsive design), Sakai QA and for Apereo we have Tsugi, Release engineering, uPortal, UX. If you can't find your  "at institution.edu" on the Apereo signup page then send an email requesting access for yourself and your institution either to sakai-qa-planners [at] apereo.org or sakaicoordinator [at] apereo.org 

The Sakai Video Help Repository
The Sakai Video Help Repository is a simple community repository of links pointing to "help videos" produced by community members.

Apereo Contacts and Mail Lists
Exstensive list of contacts and mailing lists for all Apereo projects and communities.