If they're referring to something which is not known, it's definitely "unknown". As in the opposite of "known". Something that people do not know. Information which is unavailable for perusal. Data which is not present. Stuff what aint knowed!
Jeez, are these guys too damn lazy to consult dictionary.com? Can't find an appropriate lolcat/English translator? The full extent of their improvident lackwittedness is unknown to me at this time.