Key takeaways
- A good backlink is a genuine editorial signal: it is relevant to your page, placed inside real content, and given because your work deserved the reference.
- Quantity still correlates with rankings, but the diversity and quality of referring domains matter more than raw link counts, and one strong link often beats fifty weak ones.
- Relevance beats a high authority score. A link from a smaller site that is closely related to your topic can carry more meaning than a link from a large site with no connection to it.
- Placement decides weight. Google says it tries to use links inside your main content, while sitewide footer and header links are not given much weight.
- Authority scores like Domain Rating are useful shorthand, not the actual ranking signal. Use them to shortlist, then judge each link on relevance, placement, and intent.
Every link builder eventually hits the same argument: is it better to earn a handful of excellent backlinks, or a large volume of average ones? The honest answer is that the question is framed wrong. Quantity and quality are not opposites, they measure different things. Quantity tells you how many sites vouch for a page. Quality tells you how much each vote is worth. The pages that win competitive rankings tend to have both, but when you have to choose where to spend your effort, the evidence points clearly toward quality, and specifically toward two traits that most authority scores never capture: relevance and placement.
This guide breaks down what actually makes a backlink good, using what Google has published and what large-scale studies have measured. If you want the mental model behind all of this, it helps to first understand how search engines work, because a backlink is simply one of the signals they use to decide which pages to trust.
What Google actually values in a link
Google has been consistent about what a good link is, even if the wording changes. Its spam policies define link spam as any practice that manipulates links with the intent of manipulating rankings, and it treats links that were not editorially placed or vouched for by the receiving site as unnatural. Read that in reverse and you get the definition of a good link: one that a real publisher chose to add because it genuinely helped their readers.
The mechanics reinforce the same idea. In its link best practices, Google explains that it uses links both to discover pages and to understand what they are about, and that good anchor text is descriptive, concise, and relevant to the page it sits on and the page it points to. A link is not just a vote. It is a labeled vote. The words around it, and the page it comes from, tell Google what the endorsement is for.
So three things travel with every backlink: whether it was freely and editorially given, how relevant the source and context are, and where on the page it sits. Authority is real, but it is the backdrop, not the whole picture.
Quantity still correlates, but quality explains the exceptions
It would be dishonest to pretend volume does not matter. Backlinko's analysis of 11.8 million search results found that the number of referring domains linking to a page correlated with rankings, that the number one result had on average 3.8 times more backlinks than positions two through ten, and that it had roughly three times more referring domains than the rest of the first page (Backlinko). Ahrefs, studying around 920 million pages, found a clear correlation between the number of referring domains to a page and the organic traffic it receives (Ahrefs). More independent sites linking to you is, on average, better.
But two details in that same research pull the story back toward quality. First, it is domain diversity that matters, not repetition: ten links from ten different sites are worth more than ten links from one, which is why referring domains, not total backlinks, is the metric to watch. Second, the correlation is not clean. Ahrefs notes cases where a page with links from more referring domains ranks below a page with fewer, and concludes plainly that the sheer quantity of links does not mean much if the quality is not there (Ahrefs). Volume gets you into the game. Quality decides the close calls, which are the only calls that matter in a competitive market.
There is also a scarcity point worth remembering. In the Backlinko dataset, roughly 95 percent of all pages had zero backlinks at all (Backlinko). Most of the web earns nothing. A small number of well-chosen, relevant links already puts you ahead of the vast majority of pages, which is why chasing volume for its own sake is rarely the highest-value move.
Relevance beats a high authority score
Authority scores such as Ahrefs' Domain Rating are convenient because they compress a whole backlink profile into a single number, and they do correlate with rankings: Backlinko found that a site's overall Domain Rating correlated with higher positions more strongly than the authority of the individual page (Backlinko). That is genuinely useful for shortlisting prospects. The mistake is treating the score as the thing Google measures. It is not. It is a third-party estimate of link strength, and it says nothing about whether a link is relevant to your topic.
Relevance is what turns a link from a generic vote into a meaningful one. A link from a mid-sized site that covers your exact subject sits next to related content, uses anchor text that describes your page, and reaches an audience that actually cares. Google can read all of that context. A link from a large but unrelated site, dropped into a page about nothing in particular, carries the authority number but none of the signal. When you are deciding between two opportunities, the more topically relevant source is usually the better link, even when its authority score is lower.
Placement: editorial in-content links versus footers
Where a link sits on the page changes how much it is worth, and this is the factor authority scores ignore entirely. Google's John Mueller has said that links inside the primary content area, the part of the page the content is actually about, are something Google takes into account and tries to use. In the same discussion, Google's Zineb Ait Bahajji said that sitewide links in the footer or header do not carry a very great weight in general (Search Engine Roundtable). A link earned inside a paragraph, because a writer needed to reference your work, is the strongest kind. A link stamped across every footer on a site is the weakest.
A concrete example makes the point. In one of Ahrefs' own studies, its CMO Tim Soulo describes linking out to a Search Engine Land guide from inside the body of an Ahrefs article, simply because it was the most relevant resource he found on the topic (Ahrefs). That is what a good backlink looks like from the giving side: relevant, in-content, and freely chosen on merit. It is also why editorial links are hard to fake at scale. Someone had to read your page, decide it was worth citing, and place the link where it belonged.
How to evaluate a link: a practical comparison
Put the two factors together and the difference between a strong and a weak backlink becomes obvious, even when the weak one comes from a bigger site. Here is the same page earning two very different links.
| Factor | In-content link, smaller relevant site | Sitewide footer link, large unrelated site |
|---|---|---|
| Relevance | Same topic, sits beside related content | No topical connection |
| Placement | Inside the main content, mid-paragraph | Footer, repeated on every page |
| Editorial intent | Added on merit by the writer | Boilerplate, often paid or reciprocal |
| Anchor text | Descriptive and specific | Generic or brand-only |
| Referral traffic | Reaches a relevant audience | Rarely clicked |
| Likely weight in Google | Taken into account and used | Not given much weight |
When you audit a backlink, or decide whether an opportunity is worth pursuing, walk down that list rather than glancing at a single score. Ask: is the linking page about something related to mine? Is the link inside real content or in boilerplate? Would a person plausibly click it? Was it given freely, or is it the kind of link Google's policies describe as placed to manipulate rankings? The links that pass those questions are the ones worth building, and the ones you build them with, genuinely useful pages that other sites want to reference, are the same assets that help you get cited by AI search as well.
Frequently asked questions
Is one high-quality backlink really better than many low-quality ones?
Often, yes. Volume correlates with rankings on average, but Ahrefs found that quantity means little without quality, and that pages with fewer referring domains sometimes outrank pages with more (Ahrefs). A single relevant, in-content editorial link can move the needle more than dozens of low-relevance links that Google discounts.
Should I ignore Domain Rating and similar scores?
No, but use them for what they are. Domain Rating correlates with rankings and is a good way to shortlist prospects (Backlinko), but it is a third-party estimate, not Google's signal, and it tells you nothing about relevance or placement. Treat it as a filter, then judge each link on the factors that actually carry meaning.
Do footer and sidebar links count?
They count for very little as a ranking signal. Google has said sitewide footer and header links are not given much weight, while links in the main content are the ones it tries to use (Search Engine Roundtable). A footer link can still send referral traffic, but do not expect it to lift your rankings.
What makes a link look unnatural to Google?
Google's spam policies flag links that exist mainly to manipulate rankings rather than to help users, including links that were not editorially placed or vouched for by the site owner (Google). Paid links that pass ranking credit, large-scale reciprocal schemes, and boilerplate links stamped across a site all fall into that category.
Written by Matthis Duarte, a senior SEO and organic growth expert with 10+ years of experience driving organic growth for international brands across highly competitive verticals. He is the founder of Knownful, an independent publication on SEO and organic growth featuring in-depth guides, best practices, playbooks and original analyses, including a free monthly study of which brands AI actually recommends across 10 industries.
