Macquarie Dictionary's Word of the Year 2009 (chosen by a Committee) is shovel-ready, It means, according to the report on the website " adjective: (of a building or infrastructure project) capable of being initiated immediately as soon as funding is assured."
I can't see why tweet didn't win: in fact it (at least the verb) did win the People's Choice Award . (The Committee did at least give it an "honourable mention").
Neither term is peculiarly Australian but surely tweet is much more widely used. It was (as both noun and verb) chosen (by a committee) as the American Dialect Society's 2009 Word of theYear .
Perhaps the Macquarie Committee, a member of which is Les Murray (much of whose poetry has a distinctly Australian voice) felt it needed to distance itself from the Yanks and any perception of linguistic cringe.
Shovel-ready (which IMO is two words: a Google search will show some support for this view) sounds as like a term chosen by a committee. Despite being first used (or popularised) by President Obama it doesn't seem to have caught on to the same degree as tweet.
Anyone like to put money on which of the two terms we'll be using most in a year (or 6 months)?