Extendable Protocols
It would be nice if the protocols that Hubzilla uses, such as Zot and ActivityPub, could be extended to support additional information similar to how e-mail headers work.
Any sending e-mail client can add whatever e-mail headers it wants to an e-mail. Receiving e-mail clients can choose to use those fields or ignore them.
Such a setup would allow Hubzilla forums to communicate with each other without confusing other platforms.
Platforms that do not recognize the additional fields get a basic experience. Platforms that recognize the additional forum-related fields would get an enhanced experience.