Facebook and Instagram are also really good at sussing out my interests. For example, I am a pluviophile (someone who loves rain). I don't just like rain - I absolutely love it (I would probably thrive in Seattle, Washington).

I have never sought out rain or searched for nature images or anything of the sort. But one day, it recommended that to me out of the blue. Now I get recommendations pretty regularly of all of the things that I like.