XML for everyday data
We often need to store and/or pass information in a file, or send a block of information from computer A to computer B. And the issue is always the same: How shall I format this data? Before XML, you might have considered "env" style e.g. PATH=C:\WIN95; "ini" style (grouped in sections); comma-delimited or otherwise delimited; or fixed character lengths. XML is now the established answer to that question except that programmers are sometimes discouraged by the size and complexity of XML solutions when all they need is something convenient to help parse and format angle brackets. For a quick read on the syntax rules of XML, see Introduction to XML.
XML is better because of its flexible and hierarchical nature, plus its wide acceptance. Although XML uses more characters than delimited formats, it compresses down well if needed. The flexibility of XML becomes apparent when you want to expand the types of information your document can contain without requiring every consumer of the information to rewrite processing logic. You can keep the old information identified and ordered the same way it was while adding new attributes and elements (XML Versioning).