User blog comment:Rappy 4187/Technical Update: January 13, 2015/@comment-5007040-20150115104932/@comment-452-20150115172139

For anyone else who didn't quite understand what 2Actimv was referring to:

When you visit a wiki in a different language than you have set in your Preferences, and a wiki in your preferred language exists, there is now a notification at the top of the screen.

Examples:
 * http://fr.wikia.com/
 * http://es.wikia.com/

(I imagine, but have not verified, that this only works when the other wiki is language-linked)

I think this is a pretty cool feature, and should definitely help bring attention to inter-language wikis.