User blog comment:Natsumi Thetis/The Wiki's WAM stats/@comment-7418318-20130427095030

Peak Rank is most likely the highest this wiki has ever been in the ranking, before "falling back" to the current rank again.

Probably that rank came to be due to the flurry of activity we see each time a new manga chapter is released. Especially if it's in the same week as the opeing of the new "featured X" voting.