Hidden text refers to content that’s technically present in a page’s HTML and visible to search engine crawlers, but deliberately hidden from human visitors, typically through CSS tricks like display:none, used historically to stuff keywords invisibly.
Google explicitly treats hidden text as a spam signal and can apply a manual action against sites using this technique, since it represents a direct attempt to show search engines different content than actual visitors see.
Legitimate uses of hidden elements, such as collapsible FAQ sections or tabbed content that becomes visible upon user interaction, are treated differently from deceptive hidden text, provided the content is genuinely accessible to users through normal interaction.
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