Update README.md

README.md

@@ -2,11 +2,15 @@
 # An unofficial list of official Mastodon instances
 
 This is an unofficial list of organisations that have set up a Mastodon
-instance under their own brand / identity.  
+instance under their own brand / identity, using their primary domain name.
+
+This means:
+* Yes --> social.example.com
+* No --> example.social
 
 See also: [Your organization should run its own Mastodon server](https://martinfowler.com/articles/your-org-run-mastodon.html) (Martin Fowler)
 
-**Last update**: 2022-12-06
+**Last update**: 2022-12-10
 
 ---
 
@@ -23,13 +27,12 @@ See also: [Your organization should run its own Mastodon server](https://martinf
 * OER (Open Educational Resource) Foundation: [https://mastodon.oeru.org](https://mastodon.oeru.org/explore)
 * Open Collective: [https://mastodon.opencollective.com](https://mastodon.opencollective.com/explore)
 * Open Rights Group: [https://social.openrightsgroup.org](https://social.openrightsgroup.org/explore)
-* Raspberry Pi: [https://raspberrypi.social](https://raspberrypi.social/explore)
 
 ## Opensource projects
 * ...
 
 ## Media
-* Texas Observer: [https://texasobserver.social](https://texasobserver.social/explore)
+* Tuscon Sentinel: [https://mastodon.tucsonsentinel.com](https://mastodon.tucsonsentinel.com/explore)
 
 ## Corporate / commercial / other
 * Cloudron: [https://social.cloudron.io](https://social.cloudron.io/explore)