User blog comment:Rappy 4187/Technical Update: March 10, 2015/@comment-28122555-20150312174212/@comment-452-20150318233356

Pages on the same wiki? To my knowledge, they're not page-specific, only wiki specific. I believe they're just randomised.

For instance, this should be the full list of videos for the DC wiki: http://dc.wikia.com/wikia.php?controller=VideosModule&method=index&format=raw - same list is loaded for each page. It's conceivable that the script which picks which ones to display does an analysis of the page content, but I doubt it.

edit: I think that's part of the reason they changed it from "Related Videos" to "Must Watch Videos".