I'm Aussie and I know a few people who'd say "yo".

They're exactly the sort of people who wouldn't know geography if it smacked them in the face.

It's great she's achieved what she has and good that she can encourage others. I guess the issue is that she's phrased it - "What's your excuse?" - as an assumed failing on the part of anyone not as toned and fit as she is. If you don't assume that her physique is the ideal, then "What's your excuse?" makes no sense.

What the heck is "diluted water"?

It's stand on the left, pass on the right in Australia too. And this is in a country where we drive on the left also.

Have a look at the artist's other work. She likes to do confronting things that make people a little uncomfortable. She's successfully done that here in Canberra, Australia, where all the discussion recently has been about whether the Skywhale is a horrible waste of taxpayer money or a bizarre but fascinating piece of public art.

The Dad's name is Allen Allen?

Wow! Quentin Tarantino has some skills!

What is the third one meant to be?

There's another issue at play, which is to do with gender politics. The He/She conundrum assumes a gender binary: that there are only two genders. http://en.wikipedia.org/wiki/Genderqueer

The linked twitter account is for someone who lives in The Netherlands. If you took the minimum wage there and paid it to someone in the USA, they'd be receiving a base 66% tip on everything they do. In this case they get another $3.14 on top of that! :)

If you're not too easily grossed out, you might enjoy this one of theirs as well. Very silly.
http://www.youtube.com/watch?v=3C5nE4UqqLk

I'm finding that every time I go to Neatorama now, I start to scroll down, and the page reloads. It only ever happens once each time I arrive, but it is bugging me. Any ideas?

There is no "Australian motor vehicle department". Each state (and territory) has its own. Sadly that means that only Victorians (the state that Melbourne is in) get to have these license plates. :(