Used in long uses of exclamation marks, the !1one is an intentional mistake that jokes about the appearance of numeral value "1" in exclamation overdoses. This is due to the shift key not consistantly being pressed while tapping "1" for the overused "!"'s. The intentional error may signify even more exclamation marks, like some kind of lunatic scientific notation.
Chuck : What the Heck!!!1!1!!!.
Steve : Ha Ha Ha !!!1!11!!!oneoneeleven
Chuck : Thats not funny