A very cool demo and I congratulate the author, but I am always a little sad for more data science type demos that try to answer the question (that is proving toxic) "given what I know about you, how can I find a community of people just like you?" I would love to see a subreddit finder that answers questions like "what community would complement your interests?" or "what community needs to hear what you have to say?…
It is not really based on your interests, it just takes your text and suggests subreddits where people have posted similar texts.
Otherwise, I agree on what you say. I would love to also see those kind of systems. Kind of what you get as a reaction when you talk with a mentor that surprises you ;)
Unfortunately, my skills are not there yet but I am working hard to eventually be able to build those "surprise/discovery" systems.