Black Hat positioning technique that consists of the inclusion on a web page of content hidden from the user's view, but not from the webcrawlers, who store it as they consider it normal.
Traditionally, texts were written in the same color as the background of the page, or they were reduced to a microscopic font size, until they were invisible. At present, more complex techniques are used, such as the incorporation of add-on attributes so that the text is not exposed.