The other day, I bookmarked a particularly interesting 4chan thread. Earlier today, I checked it, only to find that it had, as 4chan threads are wont to do, mysteriously disappeared. Instead of a shitstorm regarding this season's hypetrained anime, KILL la KILL, I saw only Yotsuba Koiwai, AKA the 404 girl smiling back at me.
My first thought was not "Shit, thread's gone," but "Oh, hey, look, Yotsuba!" It was then that I realized the brilliance of using her for the 404 page: having a cute loli, and what's more, a recognizable cute loli, pop up with every 404 message eases the frustration of getting a 404 message. It brings a smile to my face every time.
What do you think of 404-chan, KYM? I'm a fan, I know that. And I don't even read the manga!