Additional facilities have been built on XML 1.0 to enable integration with the Web, namely the XML namespaces recommendation, RDF and XLink. The namespaces recommendation has been controversial for several reasons but particularly because of the lack of direction given toward what a namespace name URI reference ought reference. RDDL has emerged as a reasonable solution to this issue, one which models a namespace as a proper set of resources. However namespaces do not easily work with DTDs, so accepting XML namespaces leaves the problem of how to represent DLGs in a namespace aware fashion. XLink and RDF are both W3C recommendations aimed at answering this question.
Much debate occurs as to what level of detail the commonly accepted subset ought capture.
There is general agreement that whether an XML attribute is delimited by a single or double quote character is not important. Nor is the order of attributes. The fact that an information item is an attribute vs. element and the order of child elements is significant. An RDF abstract syntax can generally be stored in a single table with three columns.