The modularization of XHTML refers to the task of specifying well-defined sets of XHTML elements that can be combined and extended by document authors, document type architects, other XML
standards specifications, and application and product designers to make it economically feasible for content developers to deliver content on a greater number and diversity of platforms.
Over the last couple of years, many specialized markets have begun looking to HTML as a content language. There is a great movement toward using HTML across increasingly diverse computing
platforms. Currently there is activity to move HTML onto mobile devices (hand held computers, portable phones, etc.), television devices (digital televisions, TV-based Web browsers, etc.), and
appliances (fixed function devices). Each of these devices has different requirements and constraints.