(XML) means a post about XML (see Gregor Hagedorn's post, "First level topics on this list (GEN)"; every post should bear a tag among RQT, XML, GEN).
By the way, this kind of tagging is much in the spirit of XML. Even in an HTML text, you can mark up a sentence, a paragraph, or words, with tags like <requirement>, <opinion>, <example>, <reference-to-article>, etc. To identify this family of tags (called a vocabulary), it is better (though not mandatory) to indicate that this fragment of HTML text is using this vocabulary (say, in this example, called authoring-discussion).
Here is a complete example:
<HTML xmlns:disc="urn:authoring-discussion" ><!-- N1 --> <!-- N2 --><STYLE> disc:opinion{color:red; font-size:large;} </STYLE> <P> Everybody agrees that ......; but I think that disc:opinionmodelizing amphibians is very important and a very special case</disc:opinion>. </P> </HTML>
You can copy-and-paste this into an example.html file, and see it in Internet Explorer 5, or Mozilla, or any XHTML+CSS1 compliant browser. For your conveniance, this file is joined to the post.
Notes: N1 xmlns is a reserved word meaning "XML namespace"; the string following = can be:
* a URN, that is an Unique Resource Name, (see RFC 2396, it's only required to remain globally unique and persistent ) as in this example, * or an URL (Uniform Resource Locator), that is something retrievable on the Internet, like http://www.w3.org/DTD/authoring-discussion.dtd , which in our example would contain a formal description of the vocabulary, a DTD (XML Data Type Definition) or another syntax like XML Schema.
N2 This is a CSS1 style; complete specification in http://www.w3.org/TR/REC-CSS1
There many topics more about XML, like:
* how and why mix several vocabularies, * how to format and query an XML document (XSLT), * what's going on in the business and scientific domains around XML * relations beetwen XML and HTML, * XML and the Web: the so-called semantic Web.
If time and popular demand are here, I could write more on this.
Cheers
Jean-Marc