Nofollow
Nofollow is a method of adding the rel="nofollow" attribute to a link to signal to search engines that the page does not endorse or vouch for the linked destination. Since 2019, Google treats it as a hint rather than a strict directive, and introduced the sponsored and ugc attributes alongside it.
- Nofollow uses the rel="nofollow" attribute to tell search engines that a page does not endorse or vouch for the linked destination.
- Google introduced it on January 18, 2005 to combat comment spam, and it originally worked as a strict directive that excluded the link from ranking calculations entirely.
- On September 10, 2019, Google reclassified nofollow as a "hint" rather than a directive and added the new sponsored and ugc attributes.
- The hint treatment took effect for ranking purposes in 2019 and for crawling and indexing purposes on March 1, 2020.
- It stands in contrast to an ordinary link that counts toward link evaluation (dofollow), and the two must be kept clearly distinct.
Overview
Nofollow is a method of adding the rel="nofollow" attribute to a link to tell search engines that the page neither trusts nor endorses the linked destination and does not wish to pass along its own page's ranking credit. Google introduced the attribute on January 18, 2005, together with Yahoo and Microsoft, to counter the spam links being scattered indiscriminately across blog comments and forums.
When it was first introduced, nofollow acted as a strict directive: search engines excluded the link from ranking calculations entirely. On September 10, 2019, however, Google announced that it would treat nofollow as a "hint" rather than a directive, and at the same time introduced two new attributes, sponsored and ugc, to allow the nature of a link to be described more precisely. The shift to hint-based treatment applied to ranking from 2019 and to crawling and indexing from March 1, 2020.
The concept stands in contrast to ordinary links whose link evaluation is counted normally, namely dofollow. Dofollow is the common term for a default link with no special rel attribute, which search engines follow and factor into their evaluation. The nofollow family of attributes, by contrast, is used when there is no intent to endorse or vouch for the destination, or to make the source of a link explicit.
rel Attribute Comparison
| Attribute | Use case | Endorsement signal | Introduced |
|---|---|---|---|
| rel="nofollow" | Ordinary links you do not endorse or vouch for, and cases that do not fit the other categories | None | Introduced 2005 |
| rel="sponsored" | Advertisements, paid links, and links created through sponsorship or compensation agreements | None (marked as paid) | Introduced 2019 |
| rel="ugc" | Links within user-generated content such as comments and forum posts | None (source identified) | Introduced 2019 |
| dofollow | Default link with no special rel attribute, carrying intent to trust and endorse | Present | Default |
Code Examples
<!-- 노팔로우: 추천·보증하지 않는 일반 링크 -->
<a rel="nofollow" href="https://example.com">예시 링크</a>
<!-- sponsored: 광고·유료 링크 -->
<a rel="sponsored" href="https://example.com">광고 링크</a>
<!-- ugc: 댓글·포럼 등 사용자 생성 콘텐츠 링크 -->
<a rel="ugc" href="https://example.com">사용자 작성 링크</a>
<!-- 여러 속성 동시 사용 가능 -->
<a rel="ugc sponsored" href="https://example.com">후원받은 사용자 작성 링크</a>
<!-- 두팔로우: rel 속성이 없는 기본 링크 -->
<a href="https://example.com">일반 링크</a>According to Google, a single link can carry more than one rel value at once, so a value such as rel="ugc sponsored" is valid and marks a link as both user-generated content and sponsored.
Background
The Google Search Central blog post (September 10, 2019, by Danny Sullivan and Gary Illyes) announced that nofollow would shift from a directive to a hint and that the sponsored and ugc attributes were being introduced. According to the announcement, all three attributes work as hints for ranking purposes, and the hint treatment for crawling and indexing took effect on March 1, 2020.
Google's official documentation (Qualify Outbound Links) advises using sponsored for advertisements and paid links, ugc for user-generated content such as comments and forum posts, and nofollow when no other category fits and you want to avoid implying an association with the linked destination. The nofollow attribute itself was first introduced by Google on January 18, 2005, together with Yahoo and Microsoft, to combat comment spam.