Daring Fireball linked to this Telegraph story about the Sarc Mark. The mark, at left, is supposed to signify sarcasm in e-mails, word documents, and so on.

Lack of inflection is obviously a big problem, now that more people than ever before communicate on a regular basis using the written word. Emoticons are the answer that has widely been accepted, but something a little more formal would be useful. I actually think that a sarcasm punctuation mark would be a useful thing, but I don't know if I'd be willing to pay two bucks for it. Maybe we should just repurpose the carat, instead? (I can hear you now: "^Yeah, sure, that's a great idea, genius.^")