The Backdrop CMS community uses a handful of tools for communication.

Live Chat

Backdrop has an official public Gitter channel that pairs nicely with the issue queue. Drop in and say hi at https://gitter.im/backdrop/backdrop-issues.

Backdrop Forum

Discuss with the Backdrop community at the Backdrop CMS Community Forum.

Issue Queue: Github

The primary means of communication is the Backdrop Issue Queue, which is where all discussion happens around adding new features or fixing bugs. Backdrop also has a handful of other repositories and queues.

Developer Documentation

The API Website contains our list of public functions, hooks, and sub-system documentation. It also contains all the change records documenting differences between Drupal 7 and Backdrop.

Weekly Meetings

Backdrop has several recurring meetings on Thursdays you should feel free to join or watch at any time. There is a weekly core developer meeting, a fortnightly design meeting and a fortnightly outreach meeting. See our Google calendar for the schedule: [iCal feed]

Google hangouts

Backdrop holds weekly meetings on Thursdays at 12noon and 1pm Pacific Time. These are open meetings that anyone can join, follow us on Google Plus to join in.

Video archives: YouTube

All weekly meetings are recorded and published to our YouTube channel. This channel is also home to tutorial videos on contributing to and using Backdrop CMS. Here are a few categories of videos that may be useful:

Twitter

Backdrop has an official Twitter account at @backdropcms.

Facebook

Backdrop has an official Facebook page at http://www.facebook.com/backdropcms.

LinkedIn

Backdrop has an official LinkedIn group at https://www.linkedin.com/groups/6930143.

Books

“Beginning Backdrop CMS”
by Todd Tomlinson
“Migrating from Drupal to Backdrop”
by Todd Tomlinson

Two great books by Todd Tomlinson, author of “Pro Drupal 7 Development”