Does anyone reading this know the earliest usage of the term "otaku" (in the uber-fan sense) in an anime or manga? All you masters of old school anime, here's your chance to show your stuff.
The earliest usage I know of is in Volume 2 of Gainax's Aim for the Top! Gunbuster (one of my all time favorites), released on January 1st, 1989 (on VHS). Noriko is called an otaku by Kazumi in the science lessons following episode 4. You can look at the translated script here: "Top wo Nerae -- GunBuster -- Vol. 2"
Takaya Noriko from Gunbuster
If you know any earlier anime or manga mentions of "otaku" (as fans), feel free to leave a comment or send me an email. Thanks!