How is this website getting amazing geo search rankings with duplicate content?

I'm genuinely intrigued by this one, as it seems to go against everything Google advises... Every page (one for every suburb in Australia) listed in this Sitemap - links to the same content (which is just an iframe). http://melbourne.subdivideyourland.net.au/post_part3.xml

Every one of these search terms (the url keyphrases) comes up at the top of SERP (in GOOGLE.COM.AU).

Is this blackhat stuff (backed by click farming et al), or just a loophole?