"Gannon Banned" is an extremely popular term used on large Nintendo and Zelda forums, and refers to when anyone misspells "Ganon" with two n's, becoming "Gannon Banned". It is used as a form of both trolling and being a grammar nazi.

According to the website gannon-banned.com, one may be "Gannon Banned" for screwing up just about anything in the Zelda universe- not only spelling errors. One may be "Gannon Banned" for:

• Spelling Ganon "Gannon"
• Calling Zelda II "The Adventures of Link"
• Claiming Majora's Mask is Zelda 2
• Calling Link "Zelda"
• Claiming the Triforce is an obtainable item, as a whole, in Ocarina of Time
• Claiming System of a Down is responsible for the "Link! He Come to Town!" song
• Claiming there is a Fourth Triforce Piece in the official series
• Claiming there is only one Link
• Claiming The Wind Waker is the last game
• Claiming there is an OFFICIAL Zelda movie
• Dissing the CD-i games (especially without playing them)
• Claiming you beat the Marathon Man
• Claiming Link and Zelda are siblings
• Claiming there is no timeline of any kind
• People who used the nickname "Reborn" for Twilight Princess
• People who believed the "Gates of the Realm" or "Reigns of Sorrow" hoaxes
• Claiming The Legend of Zelda is based on the movie "Legend"
• People who fell for the EGM TWW April Fool's Joke
• Claiming Twilight Princess is based on the film "Ladyhawke"
• Claiming Twilight Princess on Wii is superior to the GCN version
• Claiming you encountered a game-ending bug in Twilight Princess
• Claiming Zelda II is anything other than the best Zelda game ever
• People who fell for the "futuristic" Zelda hoax
• People who believed the "Valley of the Deluge" hoax
• Not realizing Sheik is an epic reverse trap
• Claiming that a Zelda game is always first and foremost developed around gameplay, not story