Preview control
Preview control describes the directives and page-level choices that shape what search systems, answer systems or crawlers may display, quote, summarize or reuse from a page.
It includes snippet controls, no-preview directives, hidden sections, rendering conditions, blocked resources and any pattern that makes a useful passage harder to surface as evidence.
Practical distinction
Preview control is not the same as access control. A system may be allowed to crawl a page but prevented from showing or extracting the passage that would make the page useful as a citation. Conversely, a page may expose too much without giving systems a clear hierarchy of what is canonical, contextual or outdated.
Governance implication
Preview control should be aligned with citation expectations. If the site wants a claim to be cited, that claim must be visible, extractable and not blocked by contradictory directives. If the claim is sensitive, outdated, conditional or non-governing, the page should make that boundary explicit rather than leaving extraction to guesswork.