In it's current, "Americanized" context: Social parasites. Usually fat, white Americans (with some exceptions) who, for whatever reason (unclear even to themselves), have chosen to become Japanese Nationalists based on their preconcieved notions of a non-existent Japanese utopia-- Notions which are developed from a lack of socialization and over-exposure to (mostly fantasy-oriented) Japanese animation (i.e., Anime, i.e., cartoons-- FROM JAPAN!)
Honesty is a bitch, huh?
Otaku: "DESU! POCKY! RAMEN! DURRRR!"