One of our customers has asked for this - basically, they want documents to have an expiry date: after that date, links to the document will fail. We intend to implement this by changing Document links 'on-the-fly' to be references to a page, with the document URL as a querystring parameter. This page will check the Summary info for the document (to which we've added an expiry date): if the document has expired a message will be displayed, otherwise the document will be displayed. We'll keep the original document URL in a span with a 'display:none' style so that we can see which page(s) reference the document from the document. A built-in solution would obviously be preferable, or can anyone think of a better method of implementing this?