First of all, I want to make one thing perfectly clear:
I WANT "USA, Australia" TO BE ADDED AS A REGION ASAP.
To demonstrate why, let's look at all 18 PC games that are considered "World" dumps: http://redump.org/discs/region/W/system/pc
Now, I've been told elsewhere that "World", at least as No-Intro defined it, is "Japan, USA, Europe". Given the nature of PC stuff, I think "World" should mean "Asia, America(s), Europe".
Age of Mythology Disc 1 and 2: Originally dumped by Nexy as USA, then dumped by Mock. Should be "USA, Australia"
Baldur's Gate: The Original Saga Disc 1 and 2: Dumped by Pikmin as Australia, then dumped by Monocrom. "Australia, Korea" seems a bit specific, so maybe "Australia, Asia"?
Doom 3: Resurrection of Evil: "Regions dumped: USA, Europe, Korea". This is correct.
Grand Theft Auto IV (World) (En,Fr,De,Es,It) (Disc 2) was "USA, Europe", and was then dumped by Pietro, as Brazillian. It is my opinion that in this case, it should just stay "USA, Europe" with "Brazil" in the comments
Grandia II (Install Disc): It says in the comments field "USA + Australia".
Interstate '76 (Disc 1) (Install CD) was "Brazil", but then changed to "World". I don't exactly know what it should be. Jackal might know.
Quake 4 and Quake 4 (Bonus DVD): Was "Australia", then "Europe, Australia", and then "World". So I suspect this is "USA, Europe, Australia". I'd probably change this to "USA, Europe".
Quake II was "Brazil", then dumped by mock. So, "Brazil, Australia", which should probably be "USA, Australia" with "Dumped in Brazil" in the comments.
Red Faction (Disc 2) (Multiplayer Disc) is odd. 3 people have dumped it, and all of them had different disc 1s. Nexy dumped a US copy, Jackal dumped a Europe copy, and Doshin dumped a Australia copy. So, "USA, Europe"
SimAnt and SimLife were both dumped by Puff0rx as "Australia", then changed to world when I dumped an American copy.
SWAT 4 (Disc 2) is was originally Brazil, then dumped in Europe. I'd change this to "America, Europe" with "Brazillian copy" in the comments.
Unreal Tournament (Disc 2) (Extras) was "USA, Europe" until monocrom dumped it. In other words, it's using "World" correctly!
Xbox 360 Accessories 1.2 was added as "World". I don't know what to do with it.
Zork Nemesis: The Forbidden Lands (Disc 2) is undoubtably "USA, Australia". There are American and Australian versions of discs 1 and 3, but disc 2 is listed as "World"
I also own a copy of Marble Drop and Microsoft Flight Simulator 98 that matches Australian dumps. And I won't verify them until the "USA, Australia" region is added.