> Anecdotally, this is true of Netflix

i thought this was a bug and I contacted Netflix about it. found out it isn't a bug, it's a feature. although i do not know anyone who would actually watch a 2hr movie the very next day after watching it in the first place. realistically their discovery algorithm is not really an algorithm, more like a static list of their own productions. i do wonder if the "like/dislike" buttons have any sort of effect, but it doesn't seem so.

> Spotify

i rarely use Spotify as a music discovery tool. i usually read reviews from various sites then I search Spotify for the exact album/song. but what i found is that Spotify can actually give me some good recommendation after i filled a playlist with songs that i like.