User blog comment:Rupert Giles/Global Navigation Update/@comment-4996890-20141204013051/@comment-11515627-20141204013619

This will probably be the last time I remind any user here, but seeing as how you have a proper petition and everything: This is just a test for the month of December.

They're pushing it site-wide to get more accurate user metrics, as well as garner proper, detailed, and measured feedback. If Wikia does decide to keep this header permanently, my guess is that it will be after there is a strong user base that supports any changes they make from here on out.