More information about tag small
Just as you can ‘highlight’ certain text - bold, italic, underlined - you can also ‘lowlight’ other text - small, crossed out, subscript, superscript text. Search engines such as Google make scant consideration of this.
Imagine that you decide to include a type of disclaimer on every web page, it is a good idea to make this smaller so that the search engines pay less attention to it and the chance of this repetition of the same text being punished with a lower value is reduced.