Google supports the “unavailable_after” meta attribute, which can instruct the search engine not to display a page in search results after a specific date and time. However, if the date needs to be adjusted later, Google may not recognize the change because it might not revisit that page before the original scheduled date passes.
This feature was first introduced in July 2007 and is mainly used for content that should no longer be visible in search results after a predetermined date, such as outdated information or discontinued products.
Recently, a Google representative shared additional insights on this topic, explaining that pages with very short lifespans—sometimes just 24 to 72 hours—can have their “unavailable_after” dates extended if necessary, providing flexibility for scenarios like time-sensitive listings or ads that can be renewed dynamically.
A web manager posed a question about using the “unavailable_after” tag to manage high-turnover listings, where ads can be renewed, thus pushing the expiration date further into the future on the fly. They asked if this dynamic shifting would harm SEO or if Google might eventually ignore such frequent changes to the expiration date.
The response from a Google engineer was that extending the “unavailable_after” date is generally fine, but it’s important to remember that Google needs to re-crawl the page to see the new date. The date acts as a signal for when to drop the page from the index, and adjustments won’t automatically re-trigger a re-crawl—they depend on Google revisiting the page. If the expiration date is changed frequently, there’s a chance Google may stop respecting it altogether.
Some experts suggest setting the expiration date only after the content has fully expired, which could mean the page stays visible in search results longer than intended. Balancing the timing and frequency of these updates is necessary to ensure proper indexing while avoiding unintended visibility.