The article here mentions the use of Data Annotations Model Binder that is available here.
Does anyone know what it's intent is? To do DA validation, I don't need a special Model binder in MVC 2.0
The first release of ASP.Net MVC didn't support validation via Data Annotations as part of the framework. The intent of the linked codeplex code was to specifically allow usage of attribute oriented validation (which was in high demand) as a stopgap to the solution that was implemented in the second release.