Freshness

Freshness is how recently the content of a page was created or changed, as far as a crawler or an AI assistant can tell from what the page and the server say. It is read from signals, not from the calendar the owner has in mind.

Where a machine reads a date

Four places, and they should agree. The server can send a Last-Modified header, defined in RFC 9110, stating when the representation last changed. The page’s structured data can carry datePublished and dateModified, both properties of schema.org’s Article type. The XML sitemap can list a lastmod for the URL. And the visible text can print a date. A page whose header says one thing, whose JSON-LD says another and whose byline says a third is telling a machine that none of them is reliable.

Changing the date is not freshness. If the text under a new dateModified is the text that was there before, the only thing that changed is a claim about the text, and a crawler that stored the previous copy can see that.

Freshness and retrieval

An assistant that answers with web retrieval fetches pages at the moment of the question, so what is live is what it reads; a page updated this morning can be quoted this afternoon. An assistant answering from training data alone knows nothing after its cutoff, however fresh the page is now. Which route a given answer used is not visible to the business, so the working assumption is the same in both cases: keep the facts on the page true, date them once, and make the dates agree.

A common question

What happens when the dates on a page do not agree with each other?

A machine can read a date in four places: the Last-Modified header, the structured data, the sitemap entry and the visible text. When those disagree, the page has effectively told a crawler that none of its dates can be trusted. Moving a date without touching the text is a separate problem, because a crawler holding the previous copy can see that the only new thing is a claim about the words. One date, stated once and repeated the same way everywhere, is what a machine can act on.

Sources

HTTP date header: RFC 9110, Last-Modified. Structured-data dates: schema.org, Article. No figures on this page are this site’s own.