Fully free/libre software available as a service, where paying for the service funds development of the software.
Monitoring and troubleshooting software and service.
Discourse bills itself as "The online home for your community: We make it easy to connect and collaborate anytime, anywhere"
Running software on someone else's computer is not the full control that we deserve of anything important to our lives, but having this software be free to potentially run on our own (or somewhere else) is orders of magnitude better than not.