I don't think it's necessary. Sarcasm doesn't work as well when you tell people you're being sarcastic. Besides, there are other ways to express sarcasm over text, so this SarcMark is unnecessary.
I'm sorry, don't use it.
I was only trying to help.
But don't ask me about it just read the about it on there website.
I'll just delete them.
It wasn't my invention.