Does anyone know how the ā€œPopular on Oppositelockā€ sidebar works? What statistics does Oppo consider ā€œpopularā€?

I ask because on occasion I have had things I post appear over on the sidebar with low views and low likes sitting there so long they become high view items, while items I post which earn high views and high likes (beating the items sitting on the side bar) sometimes never appear on the side bar.

Is there any rhyme or reason to the side bar?