Search engine rankings

hi all
can anyone tell me why a website will list well in for example, google.com, but not in google.com.au. is there a reason for this?
thanks

The reason is that Google and other international search-engines with local versions (though not all) take into account the language and location of the person who performs the query. For instance, if you're looking for a "dentist in Perth" using Google.co.uk you'll find different results than when using Google.com.au, since Google.co.uk assumes you mean the city in Scotland, while Google.co.au assumes you mean the city in Western Australia. You can spoof the results by using a proxy server that is located in the country you want results from or by changing the parameter string (replace the TLD and the language code &hl=..).

A couple factors that can be causing this:

1) The location of your site's server. A US-hosted site will have an easier time of ranking in google.com, but can have more trouble ranking in google.co.au

2) The countries where sites that are linking to you are in. If you get lots (relative amount) of links from sites in Australia, you're more likely to rank well in google.co.au