Most link audits look inwards: who links to us, and are any of those links toxic? Far fewer look outwards. Yet the links your own site publishes, to affiliate programmes, advertisers, sponsors and guest authors' websites, are just as much a part of Google's link spam rules.
When Google launched its link spam update in July 2021, it paired the announcement with a reminder to qualify affiliate, sponsored and guest post links properly. The message has not changed since. Paid links are allowed; paid links that pass ranking credit are not.
This guide shows you how to inventory your outbound links, decide which rel attribute each one needs, fix them at scale and keep them compliant as your site grows.
Key Takeaways
- Google recommends rel="sponsored" for advertisements and paid placements; rel="nofollow" remains acceptable but sponsored is preferred.
- Affiliate links, sponsored posts, paid reviews and guest post links that involve payment or exchange should be qualified.
- The July 2021 link spam update ran from 26 July to 24 August 2021 and came with Google's reminder about qualifying links.
- Google's Manual Actions report includes "Unnatural links from your site" for manipulative outbound links.
- Audit with a crawler, classify every external link by relationship, fix at the template level, and recheck regularly.
What Google asks for
Google's documentation on qualifying outbound links is short and clear:
“Mark links that are advertisements or paid placements (commonly called paid links) with the sponsored value.”
— Google Search Central, Qualify your outbound links to Google
The same page says nofollow was previously recommended for these links and is still an acceptable way to flag them, though sponsored is preferred. It recommends ugc for links in comments and forum posts, and nofollow when other values do not apply and you would rather Google not associate your site with the linked page. You can use several values together, separated by spaces or commas. Our guides to labelling sponsored links and dofollow versus nofollow links cover the basics.
Google's spam policies list buying or selling links for ranking purposes as link spam, including exchanging money for links, text ads that do not block ranking credit, and advertorials with paid links that pass ranking credit. The policies also make clear that such links are not a violation when they are properly qualified.
Why the link spam updates made this urgent
Google announced the July 2021 link spam update in a post titled "A reminder on qualifying links and our link spam update". According to Search Engine Land, the rollout began on 26 July 2021 and finished on 24 August 2021, about twice as long as the two weeks Google first expected. Search Engine Journal's coverage quoted Google's announcement:
“Sites taking part in link spam will see changes in Search as those links are re-assessed by our algorithms.”
— Search Engine Journal, Google Link Spam Algorithm Update Rolling Out on July 26
Search Engine Journal also summarised Google's guidance at the time: mark affiliate and sponsored links with rel="sponsored", mark guest post links with nofollow, and be aware that Google may take manual action against sites that do not qualify such links. The December 2022 link spam update went further, using SpamBrain to detect both sites buying links and sites used to pass outgoing links.
| Update | Dates | Type | Confirmed? | What Google said it targeted |
|---|---|---|---|---|
| July 2021 link spam update | 26 July to 24 August 2021 | Link spam | Yes | Spammy links, with a reminder to qualify affiliate, sponsored and guest post links |
| December 2022 link spam update | 14 December 2022 to 12 January 2023 | Link spam, all languages | Yes | Used SpamBrain to detect sites buying links and sites used to pass outgoing links |
Dates for 2021 are from Search Engine Land's 2021 review; dates for 2022 are from the Google Search Status Dashboard.
Which links need which attribute
| Link type | Recommended rel value | Notes |
|---|---|---|
| Affiliate links (commission on sales) | sponsored | Applies to direct affiliate links and links via redirect or cloaking paths |
| Paid advertisements, banners with links | sponsored | Including ad network links if they are plain HTML links |
| Sponsored posts and advertorials | sponsored | All commercial links inside the paid content |
| Product reviews in exchange for free products | sponsored | Payment does not have to be money |
| Guest posts where the author gets a link in return | nofollow or sponsored where payment was involved | Follow your editorial policy; qualify links the author placed for promotion |
| Links in comments, forums, user profiles | ugc (optionally with nofollow) | Can be relaxed for trusted long-term users |
| Links you do not want to vouch for | nofollow | For example, linking to a source you are criticising |
| Editorial links you chose freely | No attribute needed | Normal citations and recommendations |
Step-by-step outbound link audit
- Crawl the site. Use a crawler such as Screaming Frog (see our Screaming Frog guide) to export every external link with its source page, anchor text and rel attribute.
- Include redirects. Many affiliate links run through internal paths such as
/go/or/recommends/. Check the rel attribute on the link as it appears in your HTML, then follow where it leads. - Classify each destination. Mark domains as affiliate, advertiser, sponsor, guest author site, partner, user content or editorial. Your finance and partnerships teams can list paid relationships.
- Flag gaps. Filter for commercial relationships whose links have no sponsored or nofollow value.
- Fix at the source. Change templates, affiliate plugins, link-cloaking tools and ad components so new links get the right attribute automatically.
- Fix legacy content. Use database search and replace or your CMS's bulk tools for old posts. Test on staging first.
- Write a policy. Document which attribute each relationship gets, and add it to contributor and partner guidelines.
- Check Manual Actions. If Search Console shows "Unnatural links from your site", fix all examples, then request review explaining what you changed.
- Recrawl monthly or quarterly. Treat link qualification as ongoing hygiene, not a one-off project.
Google's Manual Actions report describes that outbound link action as follows:
“Google has detected a pattern of unnatural artificial, deceptive, or manipulative outbound links on your site.”
— Search Console Help, Manual Actions report
Where unqualified links usually hide
- Old blog posts written before your affiliate plugin added attributes automatically.
- Comparison tables and product boxes built with a separate component.
- Sponsored posts sold years ago and never revisited.
- Author bios on guest posts.
- Sidebar and footer "partner" or "friends" links.
- Embedded widgets, badges and image banners from partners.
- Press release or "featured in" pages with paid links.
What qualifying links does and does not do
Qualifying paid links keeps you within Google's policies; it does not hurt your rankings, and you can still earn affiliate income. It also does not undo past link schemes. Google's spam update documentation says that when its systems neutralise spammy links, any ranking benefit those links generated is lost and cannot be regained. If your site sold links in the past and traffic fell during a link spam update, see our link spam recovery guide and link building after link spam updates.
Affiliate sites have additional quality considerations beyond links, such as original testing and genuine reviews. Our affiliate site recovery playbook and affiliate site SEO guide cover those.
Common mistakes
- Only checking new content. Most problems sit in old posts and forgotten templates.
- Assuming cloaked links are invisible. A
/go/redirect does not replace a rel attribute on the link. - Selling "dofollow" placements. That is exactly what Google's link spam policy describes.
- Nofollowing every external link. Editorial citations to useful sources do not need an attribute; blanket nofollow is unnecessary.
- Ignoring non-cash payments. Free products, services or link swaps are still forms of exchange.
Related Guides
- Migration Problem or Algorithm Update? Diagnosing Overlapping Drops
- Should You Roll Back Site Changes After an Algorithm Update?
- Template-Level Analysis: Finding Which Page Types an Update Hit
Frequently Asked Questions
Do affiliate links need rel="sponsored"?
Google recommends sponsored for advertisements and paid placements, which includes affiliate links. Nofollow is still acceptable, but sponsored is preferred.
Will adding sponsored attributes reduce my rankings?
Qualifying paid links keeps your site within Google's policies. It does not stop you earning commission and is not a ranking penalty.
Can I use rel="sponsored nofollow" together?
Yes. Google says you may specify multiple rel values as a space- or comma-separated list.
What happens if I do not qualify paid links?
Google may ignore those links algorithmically, and its Manual Actions report includes an action for unnatural outbound links.
Do guest post links need nofollow?
Links placed for promotion in exchange for content, money or other value should be qualified. Many publishers nofollow author links by default.
Conclusion
An outbound link audit is one of the simplest compliance jobs in SEO: find every commercial link, add the right attribute, and build that rule into your templates. It protects your site and keeps your affiliate and sponsorship income safe. Read more in our post on algorithm updates and affiliate sites. If you have a manual action or need a full link audit, our penalty recovery service can help, or you can request a free quote.
References
- Qualify your outbound links to Google (Google Search Central)
- Spam policies for Google web search (Google Search Central)
- A reminder on qualifying links and our link spam update (Google Search Central Blog)
- Google algorithm updates 2021 in review (Search Engine Land)
- Google Link Spam Algorithm Update Rolling Out on July 26 (Search Engine Journal)
- Manual Actions report (Search Console Help)
- Google Search spam updates (Google Search Central)
- Google Search Status Dashboard: Ranking incident history
