If I scroll to the bottom of some pages in Kirupa.com I get a pop-up box at the bottom right of the browser screen. For example, if I scroll to the bottom of www.kirupa.com/sorts/mergesort.htm I get a box suggesting I might like Trigonometric Animations, Page 4.
Is there a page in Kirupa.com that explains how to create such boxes, or has the topic been addressed in a Forum discussion, or can someone refer me to tutorial elsewhere?
Many thanks