Because many industries have their own specific rules, unique business schemas are being designed for XML data exchange. BizTalk is Microsoft's version, while other industries and vendors are attempting to define their own schemas. One fear is that a company with the clout of Microsoft can establish the standard that best fits its proprietary needs and not that of the entire industry. Walker feels the two sites provide a similar service. That includes providing the different business schemas and DTDs that are developed in the industry, as well as ones developed for the BizTalk Framework.
Companies exist to make money and it is through product differentiation that they are able to do so.
Walker's position is a common one among leaders in the XML industry. In fact, many believe there will be numerous types of business schemas and DTDs. The world is just too complex to try to model in one DTD and schema. But clearly, most people feel its better to have Microsoft onboard with XML.org with hopes that industry consensus can be reached on the different XML schemas being created. XML has been very strong as a way to share data content.