The visitor's IP address is not always resolvable into a domain name, for example deliberately being masked to provide a Web surfer with anonymity.

And here's a chart for organization (effectively, visitor country) tracking purposes:

Being nominally located in Australia, it might be natural enough to assume that's the reason for the fairly high proportion of AU visitors (10 percent, whereas Australians make up only about 1 or 2 percent of the world's population). In fact, I know that this higher-than-expected ratio of AU visitors is largely a consequence of many visits to the page that's dedicated to Surfing, Oceanography, Tsunamis and Shark Attacks -- lots of people seem to want to find out about Australian surf spots, safety in the surf (such as how to avoid rip currents in the breaking surf), and the grim facts about white pointers or crocodiles!

PLEASE READ ON...