Google is coming out with a new tag called “unavailable_after” which will allow people to tell Google when a particular page will no longer be available for crawling. For instance, if you have a special offer on your site that expires on a particular date, you might want to use the ‘unavailable_after’ tag to let Google know when to stop indexing it. Or perhaps you write articles that are free for a particular amount of time, but then get moved to a paid-subscription area of your site. This would also be appropriate for promotional pages where the promotions expire after a given time.

The TAG would look something like

< META name=’unavailable_after’ content=Sun, 12 Aug 2007 00:01:00 GMT’>