I'm not quite sure where these rumors come from, but I personally explained how this works at Medium Day last year. The algorithm (not AI), does matchmaking between readers and stories. What we added for Boosted stories was a two step nomination by the community and then curation by the Medium team process. That's the new human part.

But existing part is also primarily human. The algorithm is playing matchmaker with a candidate pool of stories that start with the publications the reader followed, the writers the reader followed, and the topics the reader followed. I think it's much closer to accurate to say that the reader picked, not the AI.

But however you look at it, it was definitely part of my talk last year to talk about the algorithm's role in match making.