Their whole algo is good. I had it work on me recently on facebook marketplace, the only social media outside hn im still using. And its shockingly quick at finding niche things im interested in (somy cameras in a certain range, 30L osprey backpacks, im expecting it to infer my shoe size soon). and its fun. And also revealing in how it can make you want things you dont really need, if youre paying attention. Clearly bad for you. But definitely a strong (sub) product on their otherwise dismal facebook app.