You Are Not World-Ready If...
Your application is not fully Unicode-enabled
To be able to represent over 64 scripts (hundreds of languages) all at once in the English product, Windows 2000 and Windows XP use Unicode and support applications through this encoding standard. Non-Unicode applications (ANSI) are emulated by using a code-page table to make the conversion into and from the Unicode encoding.
The value of the code-page is defined by the system locale (Regional Options setting) which means that your applications behavior depends on the user's settings. You may also end up with high ANSI characters or questions marks in your UI once your application is localized.