The typographic symbol used in Spanish before a question to indicate that it's a question. If you think about, and don't jump to the conclusion that it's a really dumb idea, it kinda makes sense. Why should I have to wait until I get to the end of the sentence to know whether its a question or not? Like just then. ¿Isn't this much easier on the reader?

A useful punctuation mark used in Spanish. You use it when you begin asking a question. Unlike the question mark, which can only go at the end of the sentence, the inverted question mark goes at the beginning of the question phrase.

¿Comprendes? Es bien fácil, ¿no?

(The inverted exclamation mark works the same way.)

In HTML, it's ¿ and in Unicode it's U+00BF (191 decimal).