XML is a markup language

Why are people using XML as a slow, bloated ENTERPRISE database? XML is a markup language for documents or for objects designed to be embedded in documents. DocBook, XHTML, ODF, MathML and SVG are good uses of XML. Except for SVG, these are all marked up text. The text between the tags is usually more important than the tags. Consider a text board thread without tags. It's still readable. An HTML document without tags is plain text without any formatting, scripts, images or other elements. Hierarchical databases are not marked up text documents.

PROTIP: If you strip all the tags and don't get a plain text version of the document, don't use XML.

XML has taken off largely because of its versatility, resulting in many tools written against it. That, and the fact that the W3C promoted it along with HTML (similarly widespread). For hierarchical data storage, things like ASN.1 PER are vastly more efficient at the cost of not being easily human-readable.