XML stands for ‘eXtensible Markup Language’, a meta-language which is used to create other languages. In XML data remains marked up with tags, somewhat similar to HTML tags. Interestingly, the recently launched HTML version is called XHTML, which is based on XML and follows the syntax rules set in XML.
XML is mainly intended to be used for the purpose of storing data and information. This data further can be read mostly by machines and on a few occasions by humans also. This data is mostly stored in databases and it can be also stored in normal spreadsheets but one more specialty XML has that it can also store data in loosely structured manner i.e. data stored in letters or manuals.
Despite being very useful XML is found lagging behind the other competitive technologies like HTML. When you see a HTML page through your browser it is a nice thing and this is something XML misses out, one really needs to work very hard to make a XML document exciting. The main feature of XML is to store the data in databases and spreadsheets, so that applications can use it for various processes. There are very few areas, where XML has a supremacy over its competitors like it has its own separate structure of formatting where as HTML documents, word processor documents, spreadsheets have some mess-up because of mix structures with formatting which makes things difficult to handle content and design of a webpage. In XML certain predefined tags used for emphasizing can be placed in <em> tags for some other purpose, because a XML document never define that how the content of the particular tag should be displayed and the formatting part is left to an external stylesheet.