"Open" XML Content

As XML applications mature and enter their second generation, application developers will leverage the built-in extensibility of XML more frequently, adding new data elements to existing XML formats that first-generation applications use. How well first-generation applications work with this additional data depends on whether the developer considered extensibility in the application's architecture. Luckily, SQL Server 2000 has built-in functionality to account for additional data, even when you don't know what or how much additional data you might need to receive or send from your application. Let's explore this functionality by way of an example.

http://msdn.microsoft.com/library/en-us/dnsqlmag03/html/OpenXMLContent2.asp?frame=true