I see people talking about the AO3 algorithm all the time. The only "algorithm" there is a basic sort function, and you can control what it sorts by. But it's a user-generated-content site, so it's got to have a black-box algorithm to a lot of people's eyes. The idea of something where the algorithm is totally understandable and user-controllable is about as understandable if they'd decided to write the user interface in Klingon.