quicko: that's gold

I'm actually very unclear as to if this is an Australianism or a relatively recent global cultural development, but regardless it's a very common response in Australia today. Similar to "that's great!" but with a bit of a cooler, preppier edge "that's gold" is a the in jargon for 20-and-early-30-somethings. It can mean something is witty, clever, terribly intriguing or, occasionally, that the speaker hasn't got any other suitable comeback. That's gold.