Why do I love this word? Partly because it's appearance bears NO RESEMBLANCE WHATSOEVER to its actual meaning. If you look at it, the logical conclusion might be a type of explosion or, at the very least, a verb.
"I'm gonna interrobang your face!"
But no, it is in fact that most mundane of things: a punctuation mark, and the first new punctuation mark in two centuries! It was invented in 1962 by an ad agency: Martin K Speckter Associates. Other optional names for this most well-named of punctuation marks included "rhet", "exclarotive," and "exclamaquest." (I'm on a quest for EXCLAMATION!!!)
It' a punctuation mark that's particularly well suited to our modern culture. It adds visual emphasis to emails, tweets, and what not:
"She kissed him?!?"
Oddly, it's also well-suited for our new modern speech, where no one wants to commit to any statement that they make. Imagine the valley girl uptalk?!? That's the interrobang. It's used for rhetorical questions and, in chess notation, stands for: a dubious yet good move?!
Here's some notes on the reception of the interrobang back in the day:
The “?” at the end of “How do you do?” doesn’t always indicate just the tone of voice a writer wants to convey. The proposed interrobang, which for mechanical reasons cannot be here displayed, would indicate more accurately the degree of pleasure, curiosity and maybe surprise —all in one — the writer intended “How do you do” to deliver. An interrobang would be just right, also, to punctuate a rhetorical accusation, such as “Who forgot to put gas in the car?” where a plain question mark alone just isn’t adequate.
Wall Street Journal, 6 Apr. 1962.
And the funniest comment about the interrobang (care of http://www.worldwidewords.org/weirdwords/ww-int1.htm):
I seriously doubt if we are going to solve the problem by creating new punctuation marks. That only clutters up a language more. ... Besides, let in one man’s interrobang and you let in every nut who is trying to express the incredibility of modern life. They’ll start hanging around typographers’ shops hoping to get their own symbols into the language to solve their own emotional needs.
Life, 15 Nov. 1968. The writer, William Zinsser, jokingly suggested amperstop (&;) “to catch that delicate moment when you want to say something more and then think better of it” and the percentoquote (%”) “to suggest that the person being quoted should be only partially believed.”
Now that's harsh. Lucky for him, the American public found drugs, alcohol and sexuality to fulfil their emotional needs after 1968.
In type, it is meant to be one character:
Though, it is acceptable (though not stylistically preferred) to use long strings of ?!?!?!?!?!?!?!?!?!?!.
Wouldn't you agree that REVEEEEEEEEEEEEEEENGE! would be a very different show indeed if it were REVENGE?!?
