I think this kind of tool can be neat, and probably sometimes useful, but honestly I do not hope that tools like this become common, and used in inappropriate places. I am sick and tired of recommendations that are based on actions that are not inherently intended by me to affect my recommendations.

Take YouTube, for instance. It has gotten so bad that I actively avoid watching videos that I might otherwise want to see (even when I just want to educate myself - a simple example might be Nazi war propaganda videos), because I really don't want all my YouTube recommendations to turn into similar crap. I therefore use the service less. And I like the service less. And I think it is now more difficult for people to discover interesting videos because they largely rely on the inherent behavior pattern-matching and not robust, intentional searches. And people avoid searching for specific topics they don't want popping up on their sidebar.

I am learning that my behavior is what changes my settings, and therefore I should change my behavior if I want my settings to be good. Robust search is falling by the wayside. This is an objectively terrible situation.