Etherpad
For collaborative document editing Etherpad is hard to beat. Just log in, choose a document title and then edit. Different users will appear in different colours, and can also chat in the sidebar. This is installed as a private system in which only users on your Freedombone server will be able to create and edit documents, so it's not open to any random users on the internet.
Installation
Log into your system with:
ssh myusername@mydomain -p 2222
Using cursor keys, space bar and Enter key select Administrator controls and type in your password.
Select Add/Remove Apps then etherpad. You will then be asked for a domain name and if you are using FreeDNS also the code for the domain which can be found under Dynamic DNS on the FreeDNS site (the random string from "quick cron example" which appears after update.php? and before >>). For more details on obtaining a domain and making it accessible via dynamic DNS see the FAQ. Typically the domain name you use will be a subdomain, such as wiki.mydomainname.net. It will need to be a domain which you have bought somewhere and own and not one of the FreeDNS subdomains, otherwise you won't be able to get a SSL/TLS certificate for it.
After the install has completed go to Security settings and select Create a new Let's Encrypt certificate and enter the domain name that you are using for Etherpad. If you're using the "onion only" version of the system then you don't need to do this. If the certificate is obtained successfully then you will see a congratulations message.
Initial setup
If you have just obtained a Lets Encrypt certificate as above then go to About on the administrator control panel and you should see your Etherpad domain listed there along with an onion address. You can then navigate to your site in a browser.
Please be aware that after installation the etherpad daemon takes a while to start up for the first time. On a low powered system such as a Beaglebone Black this can take ten minutes or more. So if you navigate to the site and see a "Bad Gateway" error then don't panic. Wait for ten minutes and try again.
If you installed the system using a disk image then you can log in using the username and password which was originally shown when you installed the system. If you didn't install from a disk image then a new random password will be generated for each site and stored within a readme file. If you need to view that file then exit to the user control panel, select Exit to the command line and then run:
editor README