As part of the developments for the next degrowth conference, and also in collaboration with other organisations, we are preparing a common auth and SSO model. I think it’s important to keep this in sync as we discuss SSO also within Discourse - although I don’t fully understand if you’re talking simply of SSO (being able to login on one place and stay logged on others), or if you mean also Discourse as Auth provider.
You can see some of the discussions and developments we have been doing regarding auth and SSO here and there is also a whitepaper by Public Voice resulting from the Budapest exchange
A discussion more focused on TransforMap (and CHEST) was started here.
That said, I find that Discourse, now with the proper support for Groups and its very easy entrance point for new users (invitation based or self-subscription on topics), is also an interesting alternative to explore as an auth provider (if the functionality for being an OpenID provider is existing at all or easy to implement).
Lets try to keep the different efforts in sync, maybe also combine them, so that we can (help to) build something that serves a larger community and stays?