Marcin Dobosz is a member of Dynamic Data team in ASP.NET. He has written a great post on metadata in Dynamic Data. One of the features of Dynamic Data is instead of making the developer make the same decision on each page that uses a control to instead be able to add metadata attributes on the data model. Our controls then pick up this information and can use it automatically on any page that references that part of the data model.
Click HERE to read the great post by Marcin on how to customize WHERE Dynamic Data reads the metadata from.