Hi Anton and Jammy and thank you for a very informative question and answer.
I know that when inviting new users you can specify on which topic you want them to land (“Oh Behave…”).
I wander is it possible to setup Discourse so that every new user - including users who request access - is landed on the same topic?
The reason for this is that nobody will read the link for ToS on the registration dialog, but of course everyone will click “I have read and agree…”. That is why we want to land every new user (if approved by Admin) on the “Oh Behave…” topic, explaining the rules of civilised discussion, which in our case include some serious privacy and security considerations.
I was recently invited to a few sites that made use of the invite feature to direct me to their Welcome Topic, and it was clear that they had designed it with that flow in mind. I really enjoyed it and can definitely see how enabling community managers to design a similar experience for new users who sign up directly would be great as well.
Are you using a banner topic or anything similar to try to approximate this experience at the moment?
Some techniques we utilized to get a new user to visit a page is to link to it in the initial discobot message they receive and also place it in a dismissable banner
Our solution on invite/approval sites is to have a single category that is read-only to “everyone” and containins a single topic.
That topic outlines the processes and rules which govern the site. About 75% through the post is a paragraph which explains that the user needs to join a group to see the other categories. All other categories are protected by that group (at a minimum).
The very last paragraph (for those who try scrolling straight to the bottom) includes bogus guidelines for joining a different group. Membership of that group reveals one additional topic which tells them that they really need to go back and read the original.
We also hand out a badge to everyone who has read the onboarding topic for staff to fall back on if necessary.
The above approach has proven super effective and was the only thing which worked when onboarding volunteer makers during our COVID efforts. We went from manually onboarding a handful of people each day (with varying degrees of success) to automagically enrolling hundreds of people some days with far more consistent dissemination of our rules and processes. It’s one of those moments where Discourse has shone brightest in my ~8 or so years of working with it.
We got a category for welcome pages, user guides, FAQs, etc. One of the topics outlines basic rules of behaviour, together with privacy and security concerns (ToS). We know that all invited users can be directed to land on that page, but we encourage users to send the link to others. As pointed out, there isn’t an explicit Discourse feature to force that behaviour on users who self-register (and Admins approve them).
We quite like the solution described by Stephen, as we were already considering carrot/stick approach: users got only level 1, and have to read and agree to ToS to be elevated to level 3. But I admit I find Stephen’s solution more entertaining…
It would be great to designate a landing page other than the Latest page. For example, is there a way to mark in the URL which specific page the signup modal appears (and hopefully also where it lands them after the signup flow)?
Similar to how there are URLs for creating a new topic specific to a specified category.
Not sure of the likelihood of something more granular, for example, being able to choose a topic as a landing page (especially since admins invites already have this capability).
If I understand correctly, the invitation system allows a user to be redirected to a specific topic chosen by the inviter immediately after registration.
Could this functionality also be implemented with the standard registration system?
For example, it would be beneficial if, after registering, a user could be redirected straight to a welcome or introductions topic instead of the home page.
I’ll move this over to a 
