Fortunately, it turns out that the minimal functionality needed in order to see that the discussion group is working is in fact quite minimal, so after the pain of setting up a lot preferences, the reward comes quickly. In this example, we'll set up a minimal discussion group within our test site, simplesite.root . Inside the top-level simplesite table, create a subtable called dg . However, it is now possible for discuss.root to contain, instead of the messages themselves, just a single entry, an address pointing to the real location of the messages, which can thus be anywhere. So we will keep the messages right in our dg table.
Discussion groups run under membership.
We want it to be the case that, having posted a message, you can later go back and edit it. Your cookie securely and uniquely identifies you, so only you will have edit-access to messages that you have posted. The situation with membership information is parallel to that of messages. Originally, it was intended that membership information would be stored in members.root . But now, members.root can contain just an address pointing to a table of membership information, which can be anywhere.