DTDs can only parse character data and do not strongly type parsed data. For instance the float and integer type definitions are useless for distinguishing data with DTDs. Microsoft has turned to XML schema language to overcome type definition problems. Without schema definitions, an application receiving data must know in advanced how to interpret the data. All browsers and applications will then enjoy defined data types.
Some analyst believe that XML has a very bright future as a straightforward data format.
It is a broader and easier to understand metadata format. It will become increasingly important for applications to not only share data between applications, but also to understand what data is available from an application. Most documents passed between companies are a collection of records and tables generated by order forms, customer and product information. XML provides a practical and straightforward application integration strategy. It formats style sheets and data structures by laying the groundwork for passing data between applications without streaming a bunch of bits into a loosely defined text file.