User blog comment:DaNASCAT/Technical Update: October 3, 2016/@comment-24473195-20161006163656

"Searches will also check for and list related wikis in the right rail."

This is actually a really useful feature, although it could be improved to surface more relevant search results from other wikis. Raw pages created by contributors whether in the "current" wiki or another should almost always be surfaced above fandom.

The term "popularity" is and was always a misnomer and quite simply problematic. The only way wikia (fandom) has to assess popularity of any given item is by views and interaction, and bots can easily skew such data anyway.

A more sophisticated approach would be surfacing the top viewed pages related to the current term, or or category "members"/pages related to it, something search engines excel at. If one searches for "Angel" in the buffy wiki (if that even exists), they'd likely expect a search more in depth results that perhaps an "Angel"  wiki  (series)  would show. Leveraging WAM verticals would probably improve such search results.