That's okay :)

It started as an experiment and the initial results convinced me to make an app out of it rather than letting it be an experiment. I believe it's not possible to make a good recommendation system in general, with the limited data available about the community users. Using the HN API, I could only find user's submissions and comments (upvotes are private, thus limiting the amount of useful data). I ended up using only the submissions to determine user's topics of interest.