Stuff we learned from testers:
(1) In many ways, Keybase's chat is like Slack (except encrypted!), but unlike Slack, our user database is public and connected to known identities. So there was an opportunity we were missing, namely to teach people about teams they might be interested in, run by people they are interested in. Seems obvious now, but we had our blinders on.
(2) A large "open" team still makes sense on Keybase, even though anyone is allowed in. It's worthwhile because sender authenticity is extremely valuable. Protection from phishing attacks has been driving a lot of our team signups/migrations...especially in the cryptocurrency space.
If there are any technical questions about these changes or how teams work on Keybase, happy to answer them here. As you can tell from my HN profile, it can be proven I'm keybase.io/chris .