Do publication dates and sitemaps change whether AI assistants cite you?

Dates and sitemaps do not make an assistant cite you. What they do is tell a crawler what changed and when, so that a page you updated is re-read rather than remembered in its old form. That is worth having, and it is cheap.

The failure mode here is not absence. It is dates that are wrong, which is worse.

Which freshness signals are real?

Three, and they differ in what they cost you.

• A visible publication or update date on the page. A reader can see it, which is the

point. It has to be true.

• A sitemap with accurate lastmod values. This is the machine-readable version of the

same claim.

• A submission mechanism, for sites where minutes matter. IndexNow

describes itself as: "IndexNow is an easy way for websites owners to instantly inform search engines and web crawlers used for information retrieval ("search engines") about latest content changes on their website." Rather than waiting to be re-crawled, you say what changed.

Where you declare the sitemap matters too. The convention is a Sitemap: line in robots.txt, which is the file crawlers fetch first — Google Search Central describes that file's role as telling "search engine crawlers which URLs the crawler can access on your site."

Why is a wrong date worse than no date?

Because a date that does not match reality trains a crawler to ignore your dates.

The common version of this is a sitemap that stamps every URL with today's date on each build. It says the entire site changed overnight, every night. That claim is obviously false and it is easy to detect, so the signal stops being used — including for the pages that genuinely did change.

The same applies on the page itself. An "updated" line that moves whenever the template changes, while the words stay identical, is a claim you cannot support. Our own sitemap omits lastmod for pages we cannot date honestly, and includes it for posts, which carry a real modification date. That asymmetry is the rule: state a date you know, never one you inferred from a build clock.

What should I do, in order?

1. Put a real date on every substantive page, and update it when the content actually

changes.

1. Emit lastmod from your content's own modification time, not from the deploy.
2. Declare the sitemap in robots.txt and confirm it returns a 200.
3. Add a submission mechanism only if your content is genuinely time-sensitive. Most

sites do not need it.

1. Leave out any date you cannot justify. Silence beats a false claim.

Does republishing old content help?

Only if the content changed. Bumping a date to look current is the same false claim discussed above, made deliberately.

The alternative is straightforward: when something is out of date, fix it and record the fix. Google Search Central frames the underlying standard as "content that's created primarily for people, and not to manipulate search engine rankings" — and a date changed without an edit is squarely the second thing.

What this does not tell you

It does not tell you that accurate dates increase citations. No assistant publishes how it weighs freshness, and the honest position is that these are hygiene signals whose benefit is indirect: a crawler that trusts your dates re-reads your updates sooner. That is the claim supported by the evidence, and it is smaller than the one usually made.