The entire story is told across novels, manga, television, and video games.
According to director Kôichi Mashimo the opening theme "Obsession" had to be written in English because in Japanese the lyrics would have been profane.
As a special bonus for the fourth and final volume of the game series, Bee Train and CyberConnect2 (the companies who produced .hack//SIGN) created a bonus 29th episode entitled .hack//GIFT. In addition to a redesigned opening and a plot which features the characters from //SIGN and the games looking for a secret area called the Tasogare Onsen (Twilight Hot Springs), the episode contains radically different and cartoony designs for the characters that exaggerate their physical features.