It’s all there in Selma’ s link but Judy you’re spot on. It’s a secret formula so not open to abuse, believe it or not the old system was ‘played’ by some apparently. I believe it’s a combination of all the elements you mention. Sometimes it seems very strange that someone with more 💗s is further down the list but it’s to give those with less followers more of a chance.
Mel, Yorkshire, http://www.facebook.com/doncastercustomcakery