Idea for joinmastodon.org (those are dropdowns).
I thought about the instances.social wizard and tooter.today a lot. And I couldn't come up with any options better than interest and language. I don't think new people know what size of community they prefer, nor do they want to choose things like "untagged NSFW"
@kasaikumin languages is simple and makes sense, yes (would add it to /instance, no need for new endpoint), but I don't know how topics would work. For meaningful categorization we need consensus on terms, which means no freeform text input. But then we'd need to come up with a comprehensive list of categories to hardcode...
@Gargron I do not know whether I welcome this innovation. What about the people who don't want to associate themselves with a particular interest group?
Most users are logged on to generalist instances, aren't they?
It can also be interesting to take a look at communities you are not yet bound to.