To integrate group memberships more fluidly into the community-building aspects of Discourse posts, it would helpful to have a short-cut for inserting the join group interface directly into any post.
For example, it could be a code added to the end of a group name, e.g.
@volunteers_group:join. Whether the button appears as +Join or +Request to join or -Leave will depend on the users current membership and group security.
The button should be displayed with the group name, as well as a note indicating what priviliges joining that group offers, i.e. is it a public/private group; which categories have added visibility.
The feature would give administrators of projects the ability to bootstrap teams very efficiently.