A markup language is a mechanism to identify structured information within a document or message.
Structured information is comprised of numbers, words and graphics.
Marked up in XML, each piece of information is named for easy individual identification and location within the document. However, while people easily recognize structure, computers have to be told what documents are and what to do with them. XML, which is a relatively new language, does that, with staggering e-commerce implications. Compared to other languages when they were new, the adoption rate of XML is 'band wagon' acceptance, even from technical communities that have never been able to agree on anything in the past. Based on the comparative adoption rate to Java when it was new, demand for XML skills are increasing at a much faster rate.