Twitter and the Sarcasm Mark: A proposal

Too many are people getting into trouble on the internet these days for otherwise harmless Twitter jokes that The Man has decided is not a joke at all. 

While some of the stuff that gets the Plod involved is genuinely nasty and the authors of such filth deserve all they get, what about the innocent jokers who see their gag about - say - blowing an airport sky-high, or shooting Simon Cowell repeatedly in the face with large calibre weaponry land them in court?

What the internet needs is some sort of "This is a joke" punctuation mark that shows that the author is having a laugh and does not intend to shoot repeatedly in the face with large calibre weaponry.

In some Ethiopian languages, there is a "sarcasm mark", which looks like an inverted exclamation mark which denotes when the writer is taking the rise. Certainly, the same concept could be applied to the 140-character world of Twitter, using an underused, readily-available keyboard character. Like ~ or ^ or |.

Somebody's already had a go, devising the 'SarcMark' which has the enormous disadvantage of having to be installed on any computer that wants to use it. Basically, every computer in the whole world. Also, it appears to be a registered trade mark, which just wants me to be sarcastic. It's got to be ~ or ^ or | or nothing at all.

Of course, we already have smileys, but they're for planks, and anybody who suggests :) will see their house bombed back to the stone age and their dog worn as a scarf [twitter approved this is a joke mark goes here].

Sarcasm marks - the way ahead.