What's otaku, anyway? I really don't feel like looking it up, so a short definition would be appreciated.
Incorrect. An otaku is a person who is obsessed with anime and manga, where they own shirts, posters, figurines, and ocassionally cosplay as the person. Pretty much anybody who is overly obsessed with it. It is a Japanese term and is used in a demeaning and rude fashion. It's beyond me why Americans who like the stuff wear that term with pride when it can be very rude to call somebody that in Japanese culture. Also, hentai doesn't mean porn in Japanese. It means pervert.