The ROS Community level concepts are the ROS resources that enable separate communities to exchange software and knowledge. These resources include the following:

• Distributions: ROS distributions are collections of versioned metapackages that you can install. ROS distributions play a similar role to Linux distributions. They make it easier to install a collection of software, and they also maintain consistent versions across a set of software.
• Repositories: ROS relies on a federated network of code repositories, where different institutions can develop and release their own robot software components.
• The ROS Wiki: The ROS Wiki is the main forum for documenting information about ROS. Anyone can sign up for an account, contribute their own documentation, provide corrections or updates, write tutorials, and more.
• Bug ticket system: If you find a problem or want to propose a new feature, ROS has this resource to do it.
• Mailing lists: The ROS user-mailing list is the primary communication channel about new updates to ROS, as well as a forum to ask questions about the ROS software.
• ROS answers: Users can ask questions on forums using this resource.
• Blog: You can find regular updates, photos, and news at http://www.ros.org/news.