The Sincero-Mark and You: Partners in Earnestness

You may have heard that a company named SarcMark has trademarked a new punctuation mark intended to denote sarcasm. This new sarcasm symbol looks like a backwards ampersand (@), but since SarcMark is actually trying to sell the thing, I won't reproduce it here.
Although the free market dictates that SarcMark can charge what the market will bear, have we really come to the point where we sell each other punctuation marks? I had always been taught that are an infinite number of all the other...