The Document ID service was added to the SharePoint Server 2010 to help with the retrieval of documents in large or complex systems. It adds a field to the Document content type that provides a unique identity to that document within the site collection. This is very helpful in cases where documents move around between libraries or sites within the site collection, perhaps via a workflow, or in cases like the solution here where there are perhaps tens of thousands of documents to be sifted through.
In addition to adding the additional field and maintaining the value assignment process, there is also an additional Web Part provided that supports a form that allows the user to provide the unique Document ID. It also sends it to a redirect service that will load the document no matter where it is stored within that site collection.
The feature is nearly flawless when used within a single site collection, but in most organizations, enterprise content cannot...