XML is good- but only for some things. XML is very good at describing ordered lists, documents like they will be printed on paper, and simple trees, like family trees. For other things, XML is really bad. All other computer data with a more abstract nature has trouble conforming efficiently to the tree hierarchy of XML. Programs which use XML to describe and retrieve all kinds of data indiscriminately, suffer intense processing delays- particularly while attempting to traverse an ordered list to retrieve unordered data. The strongest feature of XML is that it's very close to the ubiquitous HTML. It's easy for many people to learn about XML because they're used to HTML. Data described by XML can be transformed into HTML very easily. XML works great to describe lists of items, like feeds of syndicated content for things like a news feed, stock quotes, or a series of audio or video episodes. It's great at describing outlines, with bigger sections broken down into smaller