Hidden text is text on websites that is not visible or hidden and cannot be seen and read by the viewer of a website. Such hidden texts are used for on-page optimization and are used on websites to manipulate search engine optimization and are detected by robots.
Hidden texts can, for example, have the same color as the background, be hidden behind graphics, photos or tables, or have a font size that has zero didot point. Texts with tiny or non-existent font size are called Tiny Text.
For search engine optimization, keywords are inserted in Hidden Text to improve keyword proximity and increase keyword density. However, search engine operators can detect Hidden Text and downgrade the website with the appropriate manipulations. The same applies to hidden links, which are intended to influence search enginerankings. Corresponding spam links are detected by crawlers, but cannot be read by people. If hidden text is detected by a search engine operator, then the website is downgraded in the ranking.
The text program Word also had the Hidden Text function. With this function, texts could be made partially invisible. This was the case for tests, for example. The teacher could make the test questions visible to the students and the test answers invisible. For themselves, the teacher could deactivate the hidden function and thus make the answers visible.