Backlinks

How do backlinks work in SEO?#

Backlinks work as discovery routes and as endorsements: Google finds most new pages by following links, reads a link from a relevant, prominent site as a sign the page is trustworthy, and uses the words in the link to understand what the page is about.

Google’s own documentation describes three jobs links do. They’re how pages get found: “the vast majority of the new pages Google finds every day are through links,” per the SEO Starter Guide. They explain what a page is about, through the anchor text and the context around it. And they’re a quality signal: Google says it looks at whether “other prominent websites link or refer to the content,” which “is generally a good sign that the information is trustworthy.”

PageRank, the link-analysis algorithm Google launched with, is still one of its core ranking systems, though Google says the implementation has changed a lot since. The logic hasn’t: a link is worth roughly what the linking page is worth to its readers. That’s why the four things below decide a link’s value far more than the count does.

• Relevance: the linking page covers your topic, so its readers are plausibly your readers.
• Editorial choice: someone linked because it helps their reader, not because they were paid or asked to trade.
• Placement: a link inside a relevant paragraph carries context. Widely distributed footer, template and widget links are on Google’s link spam list.
• Qualification: a link with no rel value can pass ranking credit; rel="nofollow", "sponsored" and "ugc" tell Google not to treat it as a full endorsement.

Do backlinks still matter for AI search?#

Backlinks still matter for AI search, but mostly indirectly: they help pages get crawled and rank in the indexes AI engines retrieve from, while the direct correlation between link counts and being named in AI answers is weak and brand mentions correlate far more strongly.

Those are correlations across 75,000 brands, and Ahrefs stresses they don’t prove cause. The mechanics point the same way, though. Google AI Overviews are grounded in Google’s core ranking systems, which include link analysis, so links help a page become a candidate. Perplexity’s crawler keeps documents from “authoritative domains” fresher in its index. Brave, the index behind Claude’s web search, discovers pages by crawling links from sites it already knows, plus reports from opted-in Brave users. Links get you into the pool; being discussed is what gets you named.

Dofollow vs nofollow backlinks: what's the difference?#

A dofollow backlink is simply a link with no qualifying attribute, which can pass ranking credit; a nofollow link carries rel="nofollow", and since 2019 Google treats nofollow, sponsored and ugc as hints it may weigh, not commands to ignore the link.

“Dofollow” isn’t a real attribute; it’s shorthand for a link without one. When Google introduced sponsored and ugc in September 2019, it said all three values are “treated as hints about which links to consider or exclude within Search,” and nofollow became a hint for crawling and indexing too from March 1, 2020. Values can be combined, as in rel="nofollow ugc".

For AI visibility the distinction matters less than it does for rankings. A nofollowed link in a well-read article still sends readers, still names your brand, and still puts you in a page AI engines can retrieve and quote.

How do you measure backlink quality?#

Measure backlink quality by counting referring domains rather than raw links, then judging each linking site on relevance, real audience and editorial placement; third-party scores like Domain Rating are useful for comparison, but Google doesn’t use them.

1. Count referring domains, not links. Fifty links from one site is one relationship; ten links from ten relevant sites is ten. Every major backlink tool reports both.
2. Check relevance. Would the linking page’s readers plausibly buy from you? Relevance is what makes a link look earned.
3. Check for a real audience. A page that ranks and gets visitors can send you visitors too. A page with no traffic is usually a page nobody chose to read.
4. Read the anchors. A natural profile is mostly your brand name, bare URLs and descriptive phrases. See anchor text.
5. Watch the trend. New and lost referring domains per month say more than any single score. Use domain authority and DR only to compare yourself with competitors.

Google’s own view is free. The Links report in Google Search Console shows your top linking sites, top linked pages and top linking text. It’s a sample, capped at 1,000 rows per table, and it doesn’t say which links are nofollowed, but it’s the only link data that comes from Google itself.

Common mistakes with backlinks#

The most common backlink mistakes are buying or trading followed links, chasing a third-party score instead of relevance, and running paid placements without qualifying them — each one risks Google neutralizing the links, or a manual action, while doing little for AI visibility.

Related terms#

• DAAuthority & off-siteDomain authorityA third-party score from 1 to 100, created by Moz, that predicts how well a website is likely to rank based mainly on its backlinks; Google does not use it, and comparable metrics include Ahrefs’ Domain Rating and Semrush’s Authority Score.Read the entry
• Authority & off-siteAnchor textThe visible, clickable text of a link, which search engines read as a description of the page it points to — so natural, descriptive anchors help, while the same exact-match keyword repeated across many sites looks manipulative.Read the entry
• Authority & off-siteBrand mentionsAny reference to a brand’s name on another website, forum, review site or video, with or without a link, and in large studies mentions correlate more strongly with visibility in AI answers than backlinks do.Read the entry
• Authority & off-siteDigital PRThe practice of earning coverage, links and mentions from news sites, publications and industry blogs by giving journalists something worth reporting — original data, expert comment, a story — which builds both backlinks and the brand mentions AI models learn from.Read the entry
• Authority & off-siteInternal linkingThe practice of linking between pages on the same website, which helps crawlers find pages, moves authority from strong pages to weaker ones and shows search engines and AI systems how the topics on a site relate.Read the entry
• Authority & off-siteE-E-A-TThe framework Google’s search quality raters use to judge whether content is credible, with trust at its center; it is not a single ranking factor but a description of what Google’s systems aim to reward.Read the entry