Ooh, that's interesting proposal. I've missed that when it has been published.

Substeems could have their own rules, but I'd like to start small and just let users to create substeems. After they've been used for a while we can see what kind of problems come up. Then a possibility to create different rules can be given to get rid of the exact problems.

What are the minimum rules for a substeem so it can actually function as a group? I'd say: subscribe to substeem and whitelist/blacklist users (as I've proposed here).

About the new tokens for substeems, I'm not sure if they are needed. My initial thought is that they will only make the system too complicated without adding enough value to the community.