Hi. I pivoted to this recently from a cross-domain recommender system (see previous Show HN[1]--it could, for example, recommend movies based on which books you like). Long story short, people thought the idea was interesting (landing page converted at ~7%, and I got hundreds of signups), but the recommendations weren't accurate enough to get people to stay (retention was nonexistent; I also did some user surveys)--and I wasn't confident that I'd be able to make the recommendations much better with the resources I have. I was originally hoping that Findka would be good enough at least to sustain growth so that I could improve the recommendation quality gradually over time, but that didn't pan out.
Findka Essays is a simplified version of the old app. It recommends only essays (instead of any type of content), and you get recommendations through email only, not through a web app. I record which links you click on, and links in future emails get picked based on your click history.
Since the domain (essays) is much more restricted, a more-or-less randomly selected item should still have a decent chance of being a good recommendation (especially since right now I manually curate most of the essays). So I'm hoping that the system will be worth using even before we have lots of data to feed to the algorithm, unlike the old Findka.
Also, I genuinely love essays (reading and writing). I think they are the most valuable form of content, and I think helping good essays spread further would have a big impact on the world. So I'm pretty excited about this pivot.
For those interested, I've written a detailed description of the architecture here.[2] The web app is written in Clojure, using Biff[3] (a web framework I made), and the recommendation algorithm is a ~100 line Python file that uses off-the-shelf k-NN, with some of my own additions for handling exploration and countering popularity bias. See [4] for details.
[1] https://news.ycombinator.com/item?id=23541840
[2] https://findka.com/blog/essays-implementation/
[3] https://findka.com/biff
[4] https://findka.com/blog/essays-implementation/#recommendatio...