Google has introduced a new META tag to set expiry date of a web page so that the page will be excluded from Google Search results after the specified expiry date.
You may get doubt why do we need to specify an expiry date to web pages? The answer is simple. An online store who is willing to setup a special discounted sale web pages for a specific period can use this tag to display the pages in Google search only till the specified expiry date.
Lets see how to set an expiry date to a page. The following META tag sets a HTML page should be removed from the search results after mid night of 15th August 2007 IST
<META NAME="GOOGLEBOT" CONTENT="unavailable_after: 15-Aug-2007 23:59:59 IST">
Read more about this at Google Web site