The benefits of UTF-8 for a multilingual website

Firstly, UTF-8 is an encoding which allows you to display complex characters (like chinese kanji or special character like in the bottom of charset tools in windows). So if you are going to use some national currency symbols, Arabic/Japanese/Korean/Chinese language, you definitely need the UTF-8. Also the UTF-8 will allow to communicate with other different software's easily, so the payment gateway integration, shipping methods and other features will be integrated without any problem with encode/decode.

Generally I can recommend the UTF-8 if you are started an new application.

• UTF-8 is a superset of ASCII. Since a plain ASCII string is also a valid UTF-8 string, no conversion needs to be done for existing ASCII text. Software designed for traditional code-page-specific character sets can generally be used with UTF-8 with few or no changes.
• Sorting of UTF-8 strings using standard byte-oriented sorting routines will produce the same results as sorting them based on Unicode code points. (This has limited usefulness, though, since it is unlikely to represent the culturally acceptable sort order of any particular language or locale.) For the sorting to work correctly, the bytes must be treated as unsigned values.
• UTF-8 and UTF-16 are the standard encodings for XML documents. All other encodings must be specified explicitly either externally or through a text declaration. [1]
• Any byte oriented string searching algorithm can be used with UTF-8 data (as long as one ensures that the inputs only consist of complete UTF-8 characters). Care must be taken with regular expressions and other constructs that count characters, however.
• UTF-8 strings can be fairly reliably recognized as such by a simple algorithm. That is, the probability that a string of characters in any other encoding appears as valid UTF-8 is low, diminishing with increasing string length. For instance, the octet values C0, C1, and F5 to FF never appear. For better reliability, regular expressions can be used to take into account illegal overlong and surrogate values (see the W3 FAQ: Multilingual Forms for a Perl regular expression to validate a UTF-8 string).

How it is possible to convert a site to UTF-8.