The Nine Network was the most popular commercial network in Australia from its beginnings in the 1950s to the early 2000s, and has been responsible for some of the most popular shows in Australian history (such as Hey Hey Its Saturday). As such, it is a beloved Australian icon.
Up until about 2000, Nine had always been the clear ratings winner in both domestic and imported shows. However, since then, all of its good programmes started finishing, leaving it without any quality shows. Only a handful of shows it has made since then (such as reality show The Block or drama Underbelly) have been successful, and any quality American show had been bought up by the Seven Network or Network Ten — in particular, Seven securing the rights to both Lost and Desperate Housewives in 2005 is generally considered to be one of the main reasons Seven overtook Nine as the most popular network.
Nine is currently treading water, thanks mostly to the rights it holds on a wide range of sports such as Cricket, Rugby League and the Olympics as of 2010. It's still somehow coming second in TV ratings (possibly thanks to Two and A Half Men and The Big Bang Theory, given how much they're showing them). They also currently have the Australian rights for Top Gear, which underwent a Channel Hop from SBS; in addition to running the original, they've also done a far less successful Australian version. Also, for some reason Nine picked up the rights for an Australian version of Top Design in 2011... three years after the US version was cancelled.
Nine also owns and operates two other free-to-air digital television channels designed to complement the primary Nine channel: GO!, oriented at a teen/young-adult audience, and GEM, covering a wide range of entertainment but generally favouring female-oriented programming. In many parts across Australia's east coast, Nine's regional affiliate is WIN Television, which also manages the regional distribution of GO! and GEM; for the most part, the only difference between the programming is half an hour more news and half an hour less Two and a Half Men or whatever else Nine is adoring at the time.
For news, Nine partners with ABC from the United States. This is best reflected in their choice of news theme, a remix of the famous Tar Sequence theme from Cool Hand Luke, which was the news-theme mainstay of many an ABC affiliate until the early 90's.