My official response to the new punctuation marks that have been proposed recently, such as the “sarc mark” and others:

This is the doubt point. It is used “to end a statement with a note of skepticism.” What do you think? I don’t dislike it. Hey, I’m good with ending many sentences on a note of skepticism. It’s like saying, “Uh huh” or “I’m sure” in a sarcastic tone of voice, only with punctuation.
I just heard about the “sarc mark” yesterday on a podcast, which is why I looked up weird punctuation marks this morning. Obviously the sarc mark is meant to signal sarcasm. Here it is:

Some guy who invented this also copyrighted it, so I guess you can’t use it without permission. That sure seems like a great way to get your new punctuation mark into widespread use [sarc].
I would assume that none of these would ever be successful in breaking into the wider world of real punctuation, except that the podcast mentioned that the interrobang — looks like this —

— was actually included on typewriter keyboards in the seventies. Of course, it’s not on keyboards now, which suggests that getting a new punctuation mark accepted is definitely an uphill struggle. If you are interested, here is the Wikipedia entry on the interrobang.
I like the Calibri version the best, but I never actually use Calibri, so I guess I won’t be inclined to use the interrobang either. Also, I don’t think I have ever seen anybody use it ever. I truly dislike the ?! or !?! type of punctuation — except on social media, it’s perfectly okay there — but who knows, I might feel differently about the interrobang if people actually started using it.
Which I don’t think they will.
On the other hand, practically everyone uses smileys now. So maybe I’m overly doubtful.
How about it? Do you think you’d use sarc marks and doubt marks and the rest if those keys were right there on your keyboard? I might — on social media only. I think it would drive me nuts to see those marks in a novel. Except maybe a near-future SF novel. In that case, new punctuation marks might be fun.