The Microsoft Office platform allows you to maintain both standard and custom properties for documents. Document Information Panels, however, let you implement additional functionality such as metadata-based search and automation of information-driven business processes is Office documents and SharePoint apps.
In the April 2008 issue of MSDN Magazine, Ashish Ghoda demonstrates how you can build Document Information Panels in the Microsoft 2007 Office system to capture and manipulate metadata in Office documents.
Don't forget to browse the sample code in our online code library.
Be sure to check out our MSDN Magazine archives for more articles about Office and SharePoint development.