This graph on Valleywag would be far more informative if it indicated how large each of those markets is.
While Google search is clearly dominating the Australian market, because the graph doesn't tell us the size of the market, we don't know if Google's far smaller market share in Japan is in fact a less substantial market for it.
I'm not saying that the graphs isn't useful and interesting. It is extremely important to know how much of the market each company controls and it is one of the only objective ways to tell which search company is "winning" in those places. I'm simply pointing out that the raw numbers are essential to a full grasp of the relationships between Google, MSN and Yahoo.
I will try to find the raw numbers as to the size of these markets and post them later...