Otaku is a Japanese word used for foreigners who are obsessed with Japanese culture. A lot of confusion has been made over the years, and people are starting to think Otaku is someone who stays home all day and does nothing but watch anime and jerk off to pictures. This is called a Hikikomori. The difference is that Otaku get out, and have a life, and pass in school, regardless by how much, and talk to other people, depsite the topic. Hikikomori are shut ins, and do leave the house for anything and don't socialize. For any reason. Whatsoever.
Delivery Man : You there?
Hikikomori : *Fap fap fap fap*
Delivery Man: I have a package for a Mr. Smith
Hikikomori : *Opens door naked* Thanks! *closed door and faps*
Otaku 1: Hey, did you hear? They're coming out with a new season for Naruto!
Otaku 2:Naruto is gay, you have to watch anime that deals with Japanese life, like Clannad. You're a fake.
Fake-Otaku 1: No way, Bleach is better than anything.
Otaku 2: Whatever.
Japanese Guy 1: God-damn-it. I hate those Otaku's
Otaku 2: OMFG A REAL LIFE JAPANESE GUY!!! HIIIII!!!!
Japanese Guy 1: Fuck.