Private channels / topics?

Yes, as of now, admins and moderators can create private invite-only chat channels. I could add security settings to let non-staff community members create private chats, too, like in Slack. — I didn't enable that yet, because I was worried that non-staff members could then create their own somewhat "inisible" chat channels, and start talking about weird things. (What do you think?)

Admins can access private chat channels. Currently they'll even get notified, if one is created and the admin listens to new-topic notifications. (What do you think about this?)

Can I ask what's your use case? Who are the people who will create private channels, and what will they talk about?

(I remember at my last job, we were using Slack, and we the developers had our own private Slack channel, that others couldn't see. A bit like "don't look into the sausage factory".)

Here's how to create a private chat (if you're admin or moderator):

Click the (+) icon, like in Slack:

Then, click the topic type button:

Choose "Private chat":

Type a title and purpose, and click Create chat. Then you'll see the chat page, and can click Add more people to the right, to "invite" others. They're curently just added directly to the chat; they don't get any "Do you want to join?" question.

What do you think about all this?

I'm thinking, most people will not think about clicking the topic type button, then look at all alternatives and find "Private chat". — To make private chats more "discoverable", maybe instead, when one clicks (+) to create a chat, there could be a modal dialog that asks if one wants the chat to be private, or everyone-may-join.