XML
XML is an acronym for Extensible Markup Language, a simple and flexible text-based programming language used in conjunction with HTML. XML is useful for data exchange and the creation of customized tags.

XML Feed
An XML feed is a form of Paid Inclusion or Search Engine Submission in which an XML document is used to provide a search engine with information about multiple web pages. An XML feed is particularly useful for multimedia sites or database sites that draw a variety of relevant search queries.