As noted earlier, its Related Pins recommender system drives more than 40 percent of user engagement. However, trying to stuff that into a user-item matrix would cause a whole host of problems.

I love music, I use Spotify, and I can program... so I naturally put all three together and built a program that recommends me new music.

A new approach to recommender algorithms, hidden behind proprietary walls, could help digital platforms filter content more carefully.