I’ve given up on content-based recommendation. The issue is that people’s interests in their topics and subtopics is primarily dictated by their individual circumstance and environmental real-world context. That is, if you are able to perfectly know the interests of an individual today, perfectly label the topic of all content, you’ll still give them incorrect content after a few days—-and with news article recommendations, by the next session of platform engagement (since they’ve sufficiently extracted the maximum value from the present topics by the nature of the session).