203C;DOUBLE EXCLAMATION MARK;Po;0;ON;<compat> 0021 0021;;;;N;;;;;
  203D;INTERROBANG;Po;0;ON;;;;;N;;;;;
  2047;DOUBLE QUESTION MARK;Po;0;ON;<compat> 003F 003F;;;;N;;;;;
  2048;QUESTION EXCLAMATION MARK;Po;0;ON;<compat> 003F 0021;;;;N;;;;;
  2049;EXCLAMATION QUESTION MARK;Po;0;ON;<compat> 0021 003F;;;;N;;;;;

I first heard of it back when Usenet was still the hotness.

Apparently it's been around for close to a century, so if it hasn't caught on widely by now, you're probably right.

On a typewriter, you could type one punctuation mark, backspace, and then type another.

Even once computers added the interrobang to Unicode (or older systems), you either need to type in a numeric code, use a secret bucky bit, or select it from a graphical UI, none of which is worth it for more than the odd weirdo with a whimsical streak.

And yes, I love the interrobang! Ever since I mapped scroll lock to "compose" on my keyboard, I've had fun typing all sorts of characters :)

And to show off another fun character, for languages like Spanish that start a question with an inverted question mark, there's also ⸘, the inverted interrobang.

Though I find the name some people call it, gnaborretni (interrobang backwards), much sillier.