Several years ago I used to use a music service that had a bunch of sliders, something like:

    Favorites:  Normal <----------> Very Frequently

    Artist:  Liked only <-----------> Wide variety

    Prefer:  Old <----Balanced----> New

    Popularity:  Hits only <--------> Fringe 

It was great to be able to customize stations. I don't remember what service it was, but I think it did get purchased and folded into something else.

This was a great way of tweaking the "randomization", and really gets into understanding what people want to hear. In my case, I had different stations/playlists customized in different ways.