Encoding. If it's done properly, your visitors will never even think about it. If it's not done properly (or at all), some of your international visitors may not even be able to read parts of your site--and that is definitely not a Good Thing.
For the impatient types out there, English language files should include the following meta tag in the <head> area:
Note: preceding markup is superfluous to, inferior to, and superseded by server-specified encoding.
Simply speaking, "encoding" refers to the language in which the content of your HTML or XHTML page is written, and it is specified by a single line of code. If you do not specify your encoding, browsers visiting your site will attempt to figure out which encoding to use. In practice, though, browsers will end up trying to read the page in the language that the user has specified as their default. This means that if you have an English speaker visit your English language site, they probably won't notice the difference even if you don't specify your encoding. However, non-English speakers will most likely see a jumble of characters or ASCII gibberish whenever you use a special character (in other words, anything that you cannot type directly from your keyboard--arrows, curved quotes, em dashes and ellipses are some examples).
As we mentioned at the top, if you specify the proper encoding, the visitor will never realize that anything has been done--and isn't that the way it should be? If you are interested in becoming a broad-minded, responsible web designer, always specify your encoding. Your international visitors will thank you.
And, if you do decide to use ISO-8859-1 encoding, the W3C has a handy list of character entity references that you will want to use for high-bit characters (what I referred to as "special characters" above--curly quotes, em dashes, etc.).
[This FAQ entry has been brought to you by the Society for the Promotion of Encoding Awareness.]
