The rel=”nofollow” attribute is a link management directive that is added to a hyperlink in the HTML code. It functions as a protocol instruction to search engine crawlers not to pass authority or “link weight” (Link Juice/PageRank) from the originating page to the destination URL. Literally, it signals to the search engine that the link does not represent an editorial recommendation or vote of confidence.
Historically, nofollow was introduced by Google in 2005 as a measure to combat comment spam, where automated bots used comment sections to inject links to their sites for the purpose of ranking manipulation. Subsequently, its use has expanded to include any paid, sponsored, or user-generated links that are outside the editorial control of the site owner.
Although Google has introduced more differentiated attributes such as sponsored and ugc, nofollow retains its fundamental importance as a general mechanism for isolating links from the authority scoring system. It is a key element in ethical SEO and in complying with search engine guidelines, preventing artificial distribution of link weight and contributing to the honesty of the link model.