How ‘unavailable_after’ Should (But Won’t) Be Used

A couple weeks ago, Jill Whalen’s High Rankings Advisor broke the Story about a new metatag Google will soon recognize. While still in the planning stages, the “unavailable_after” tag will tell Google (and presumably, any other engines that choose to recognize it) when the content on a specific URL “expires.” In other words, proper use of the tag will ensure that page is no longer crawled — and more important, that page won’t appear on results pages after the date input in the tag’s “content” attribute.

Following, ways this tag could potentially be used by marketers and SEOs.

Auction Listings

As searcher frustration goes, few things are as tantalizingly annoying as seeing the exact item you want on a search engine results page, only to click over to the auction site and see that the auction ended. (And it’s even worse when the winning bid was within your budget!)

In researching for this article, the very first query I tried, “used skateboard,” turned up just such an expired eBay auction on the first page. For what it’s worth, the second sample query, “autographed rush 2112 album,” turned up an expired eBay auction also, this time in the top spot. The third query, “pac man machine,” brought up an expired classified on Craig’s List. So I can confidently say out-of-date information is widespread in search results, particularly at the retail level.

In theory, the unavailable_after tag is tailor-made for auction pages and classifieds, as well as other types of pages such as real estate listings and “special offer” pages. Auctions end at a specific time, while classifieds generally expire after a set period unless they’re renewed. Would an ideal user experience consist of these pages disappearing from the index immediately after the auction or listing expires? Many would argue yes.

But the users don’t get to decide. eBay and Craigslist deal differently with expired listings. Craigslist simply abandons you on a page that says “This posting has expired,” leaving the user with little more than a set of breadcrumb links at the top that may lead to a similar ad if you click.

eBay, on the other hand, is a bit more sophisticated. Within a few seconds of the page loading (and discovering the auction has expired), the site soon adds several links to current auctions selling “similar” merchandise. I’ve occasionally criticized eBay’s misuse of PPC keyword inventory in the past, so to be fair, I believe the way eBay deals with expired auctions is just about as user-friendly an experience as we could expect.

Given the ability to generate similar, current auctions, why would eBay entertain the thought of forfeiting the visit? It wouldn’t. Even Craigslist, with its lackluster response to ad expiration, is bound to keep some of that traffic on its site. And some beats none.

Subscription-Based Content

We have some large media clients with various paid content policies. When first reading of the “unavailable_after” tag, I was enthused about the potential opportunities that lay ahead, specifically for clients whose “free” content converts to “paid” status after a week or month. But the other options currently in place, such as using a 301 to redirect articles to new “paid-only” URLs, or simply telling the database to trigger the password barrier upon expiration, eventually regained their spot atop the list. As an SEO consultant, I’d be crazy to recommend anything else.

The “unavailable_after” tag will thrive only in environments in which the continued presence of information will produce a negative impact on controlling parties, and where there’s little benefit to redirecting to another part of the site. For example, certain class-action lawsuits require information for potential victims be posted on the Web for a specific length of time. Defendants eager to minimize the toll taken on their brand will likely benefit from this sort of tag. The sooner any trace of such information disappears, the better.


It’s frustrating to search for something like “current search engine market share” and be led to a page that considers “current” to be 2003. But that doesn’t necessarily mean I want that page to drop out of the index. There’s an equal chance that some day I’ll need the 2003 information for a presentation. At minimum, perhaps the raising of this point will encourage us all to categorize, title, describe, and link to our content more accurately.

The “unavailable_after” tag is a wonderful example of how engines are making large efforts to bridge the gaps in Webmaster communications and to improve the search experience. But for the tag to garner significant use and begin to provide benefits to the user experience, usage must provide significant benefit — benefit far beyond the kudos and recognition that accompany contributing to the greater good.

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