Whenever you design or write for a web site that has an international audience, make sure you address each market. It pays to undertake detailed keyword research into your markets you are targeting so you can capture the correct regional jargon and spelling that people are searching for. Remember it’s not enough to think global, you’ve got to act global too.
If you will do business in more than one market, do yourself a favor and write a keyword-optimized landing page for each market. If your markets are distinguished by countries and geographical boundaries then take the time to learn the differences in the language. The author of the above article makes a very good point: English is different in America than in England and Australia. British English has its own rules and if you will be doing business in America and the UK then you should create a landing page for each market.