To contact the managers of the association, please write an email to firstname.lastname@example.org (replace invalid with org).
Salut à Toi's multi-user chat room is the best place to discuss the project. There are many ways to join it, for example using Libervia, but if you prefer to not create any account, just click the following link: xmpp:email@example.com. Please note that you can't send an email to this chat room: its identifier looks like an email address but it's not!
On the main developer's blog, you'll get recent information/reflections about SàT's features (and also more general ones): http://www.goffi.org
You can subscribe to the users mailing list to follow the progression, give your opinion and contribute: http://lists.goffi.org/listinfo/users
You'll find some user documentation on the wiki: http://wiki.goffi.org/wiki/Catégorie:Documentation_utilisateur
SàT is an open project: come and discuss, give your opinion and share your thoughts. The more people that participate, the better the project will be. Share your view not only on technical points, but also on philosophical or political ones. And if you are around, come to have a talk in real life :)