It is supposed to indicate how high the person's voice is at the end of the sentence. If there are 3 question marks, the voice gets really loud at the end. Many question marks in a text can define a sense of confusion and anger. A single question mark is used to ask a question; several question marks or several question marks together with exclamation marks are used to express confusion.
It's absolutely rude and should never be used. This is because a single question mark is sufficient to indicate that the sentence is actually a question. Two question marks indicate a much more questioning question. Three are for very, very, REALLY questioning questions.
More than three is a mistake. The upside-down question mark in the middle of a sentence Often times, the upside-down question mark is placed at the beginning of a question. When punctuating sentences with parentheses, the rules for using question marks are almost identical to the rules for using quotation marks. The Riddler is known for his sharp intellect and believes that life is full of questions (also known as riddles).