Difference between follow, nofollow, sponsored, and UGC links

Google recognizes four attributes for the rel element of a link: dofollow (default), nofollow, sponsored, and ugc. Each one communicates something different to crawlers, and confusing them can affect how a site is indexed or how authority signals are distributed.

A technical comparison of rel link attributes, with examples of when each applies according to Google's guidelines.

The rel attribute of a hyperlink has existed long before Google expanded its vocabulary in 2019. Until that year, however, only one practical distinction existed: a link with nofollow or a link without it. The introduction of sponsored and ugc as separate attributes marked an important conceptual shift: Google stopped simply asking sites to block a link's signal and started asking them to describe it. This article explains what each attribute does, when it should be used, and what the consequences are of not implementing them correctly.

What each attribute means and how it works at a technical level

Before diving into use cases, it helps to have a clear definition of each one.

Dofollow (or a link without a restrictive attribute)

The term "dofollow" is technically informal: there is no rel="dofollow" attribute in the HTML specification. A link is dofollow by default when it carries no rel attribute indicating otherwise. This tells Googlebot that it can follow the link, crawl the destination, and potentially transfer PageRank signal. It is the type of link that can deliver the most value in a linkbuilding campaign when it comes from a relevant, authoritative site.

To understand how Google processes and distributes that signal across pages, it is worth reviewing How PageRank works and its relationship with backlinks, which details the mechanism behind authority transfer.

Nofollow

The rel="nofollow" attribute was introduced by Google in 2005 as a tool to combat comment spam and link farming. Its original function was unambiguous: tell the crawler not to follow that link or transfer PageRank through it.

In September 2019, Google modified how it treats the attribute. From that update onward, nofollow became a hint rather than a directive for crawling and indexing purposes. In practice, Google may choose to crawl a link marked with nofollow if it determines the link has value for exploring the web graph. That said, PageRank signal is still not transferred directly. This distinction matters: a nofollow link on a high-authority site can still drive referral traffic and visibility, even if it does not pass authority the same way a dofollow link does.

Since 2019, nofollow is a hint for crawling, not a directive. Google may choose to follow the link, but it does not transfer PageRank through it the same way it does with a link that carries no restrictive attribute.

The rel="sponsored" attribute was introduced alongside ugc in the same 2019 update. Its purpose is to identify links that are part of commercial arrangements: advertising, sponsored content, paid link exchanges, or any link whose existence involves monetary or material compensation.

Google had already required this type of link to carry nofollow. The introduction of sponsored did not change the underlying obligation — these links still should not transfer PageRank — but it added semantic granularity. In terms of crawling and indexing, sponsored receives the same treatment as nofollow: a hint, not a directive.

The correct use of sponsored is relevant in the context of white hat, grey hat, and black hat linkbuilding practices, where transparency about the nature of a link is part of Google's quality guidelines.

UGC (User Generated Content)

The rel="ugc" attribute is designed for links generated by users within a platform: blog comments, forums, Q&A sections, public reviews. The rationale is that the site's publisher has not editorially validated or endorsed those links; they are simply hosted because a third party produced them.

Like nofollow and sponsored, ugc has functioned as a crawling hint since 2019. Google may choose to crawl those destinations, but it does not treat them as editorial endorsements from the hosting site.

When to use each attribute: a practical guide by link type

The most common source of confusion is not understanding what each attribute does, but knowing which one applies in each specific situation. The following classification covers the most common cases.

When NOT to use any restrictive attribute (dofollow)

A genuine editorial link from your content to an external reference source.
Internal links between pages on the same site (100% of internal links should be dofollow except in very specific technical circumstances).
A link from a guest post article you published as an external author, when the arrangement did not involve monetary compensation.
A backlink you received organically from another site: you cannot control it, but if the editor asks, there is no reason to request a nofollow if the link is relevant.

When to use nofollow

When you do not trust the destination but need to mention it (for example, linking to a source to refute its argument).
In third-party widgets or embeds where you cannot guarantee the quality of all destinations.
As a generic fallback when the CMS does not offer a sponsored or ugc option and the link is not editorial.
On login pages, payment gateways, or any URL that should not receive page authority.

When to use sponsored

Sponsored posts or native advertising where the advertiser paid for the mention or the link.
Banners and display ads with a hyperlink.
Affiliate programs: every affiliate link must carry rel="sponsored" according to Google's current guidelines.
Link exchanges involving monetary or in-kind compensation (free product, discount, etc.).

When to use ugc

Blog comments open to the public.
Forum or community replies where users can freely insert links.
Product reviews with a free-text field where users can add URLs.
Author bios on multi-author platforms where any registered user can publish.

Combining attributes: when and how it can be done

Google allows combining rel attributes on the same link. This is technically valid and, in some cases, semantically more precise. For example:

<a href="https://ejemplo.com" rel="ugc nofollow">Texto del enlace</a>

This markup indicates that the link was generated by a user (ugc) and should also not transfer PageRank (nofollow). The combination reinforces the signal, although in practice Google already treats both attributes similarly.

Another valid combination is rel="sponsored nofollow", useful on platforms that have not yet updated their templates to support sponsored independently but want to be explicit about the commercial nature of the link.

What makes no technical sense is combining two contradictory attributes that describe the same dimension, such as rel="sponsored ugc" on the same link: a link cannot simultaneously be an affiliate link and user-generated content.

Common mistakes and their implications

Knowing the attributes is not enough; implementation errors are common even on sites managed by technical teams.

Applying nofollow to all outbound links as a precaution

Some publishers apply nofollow broadly to all their external links to "avoid losing PageRank." This practice does not produce the intended effect: Google does not internally redistribute the PageRank "saved" from nofollowed links. Moreover, marking a genuine editorial link as nofollow can be interpreted as a signal of low confidence in your own content.

Not marking affiliate links as sponsored

Affiliate links without rel="sponsored" constitute a violation of Google's webmaster guidelines. Although a manual action for this reason is not automatic, the practice creates unnecessary risk, particularly on sites with a high volume of monetization links. Google has been explicit about this in its official documentation on link attributes.

Confusing ugc with nofollow on proprietary platforms

On platforms with active comments, some developers apply generic nofollow instead of ugc. This is not a serious error — Google treats them similarly — but ugc provides more precise semantic information and has been the recommended practice for user-generated content since 2019.

Removing the rel attribute from internal links without a technical reason

Adding nofollow to internal links — for example, toward login or legal pages — was a popular practice before Google clarified that "saved" PageRank is not redistributed. Today, the recommendation is to use noindex on the destination page if you do not want it to appear in search results, rather than nofollow on the incoming link.

Assuming nofollow equals complete invisibility

Since the 2019 update, nofollow does not guarantee that Googlebot will ignore the link. If you want a specific URL to go uncrawled, the right tool is the robots.txt file combined with meta robots — not the link attribute.

This point is especially relevant when designing strategies around types of links in SEO, where the distinction between controlling crawling and controlling PageRank transfer defines different tactical decisions.

Practical impact on a linkbuilding strategy

The type of attribute a backlink carries matters, but it is worth calibrating how much weight to give it within an overall strategy.

A dofollow link from a high-authority, topically relevant domain is, all else being equal, more valuable for rankings than the same link with nofollow. This does not mean nofollow links lack value: they drive referral traffic, can influence brand perception, and contribute to a diversified, natural backlink profile.

In fact, a backlink profile composed exclusively of dofollow links from niche sites can raise flags in Google's quality algorithms. Diversity of sources and attributes is a signal that the profile is organic.

For anyone building a strategy from scratch, the starting point is understanding what linkbuilding is and what role it plays within off-page SEO. The article What is linkbuilding and why it matters in SEO covers that context before diving into