The tech community in Australia, while close knit and growing, has nothing on San Francisco (but honestly, where in the world does?). There is also the lure of other big, well known cities, particularly New York. Australians love to travel, and coming to the US is pretty expensive, so perhaps pitch it as a way of being close to north and south America?

That's why I'm here. I don't plan on returning to Melbourne until I've lived in San Francisco and New York either. It's a hell of an opportunity once you're over here.