The symbol – a dot inside a single spiral line – can be installed onto any PC running Windows 7, XP or Vista, as well as Macs and Blackberry mobile devices.
It can then be used in Word documents, instant messenger conversations, Outlook email and other programmes, just by pressing Ctrl and the full stop button.
Presumably the recipient of the sarcasm has to also fork out $1.99 to actually see it?
Otherwise what - some random "unknown" glyph or the raw unicode presents itself.
So rather than your recipient think you're being sarcastic, they instead think you're an idiot who can't use a keyboard.