I would like to discuss a new Tag #matrix.org for SuperUser.
What is Matrix.org
The Matrix.org is an Open Source, decentralized, distributed, chat protocol to have private and group conversations. It supports easy interconnection to IRC, and server-side applications to bridge Matrix.org users to Telegram, Slack and so on.
Adoption
Matrix.org has a lot of official and not-official Open Source chat clients. The most famous is probably Element.io, available on Android (also from F-Droid), iOS, and Linux desktop (also via snap) and also as web application.
It's interesting that in 2020 they received 5 million dollars of donations just from Automattic (company behind WordPress).
https://matrix.org/blog/2020/05/21/welcoming-automattic-to-matrix
Proposed description for the tag
Matrix.org is an open, decentralized, distributed protocol. In-topic questions include: problems about Android and desktop clients. Off-topic questions include: specific web client (ask in WebApps); programming over this protocol (ask in StackOverflow); and server-side errors on a Matrix server (ask in ServerFault).
In-topic considerations on Stack Exchange
The WebApps network can host in-topic questions related to a very specific web-app of the Matrix protocol, like https://app.element.io/. For this case I would suggest to propose in the WebApps network a new tag #element.io (not to be discussed there).
The StackOverflow network can host in-topic questions about software programming related to implementations of a Matrix.org client or something like that. For this case I would suggest to propose in the StackOverflow network a new tag #matrix.org (not to be discussed there).
The ServerFault network can host in-topic questions about how to fix server-side errors related to hosting a Matrix node. For this case I would suggest to propose in the ServerFault network a new tag #matrix.org (not to be discussed there).