Backlink
A backlink is a hyperlink from a page on another website that points to your page. Search engines like Google read backlinks as votes of confidence, using them to gauge a page's authority and relevance and to discover new pages, which makes them a core off-page SEO signal.
- A backlink is a link from an external site to your page, and it is one of the strongest signals search engines use to gauge a page's authority and trustworthiness.
- Quality matters more than quantity. Google's John Mueller has said the total number of links "basically doesn't matter at all," and that a single good link can be decisive.
- The six attributes of a good backlink are authority, relevance, anchor text, placement, the destination page, and whether it is dofollow (Ahrefs).
- Google recommends marking advertising or paid links with rel="sponsored", user-generated content links with rel="ugc", and other links you don't want to vouch for with rel="nofollow".
- Manipulative tactics like buying, swapping, or building PBN links violate Google's policies and risk penalties, so the goal should always be to earn backlinks naturally.
What Is a Backlink?
A backlink is the hyperlink created when one website links out to another. From the receiving site's perspective it is an incoming link, so it is also called an inbound link. Search engines treat it not as a plain connection but as a recommendation: when a reputable site links to your content, it effectively tells the search engine that the page is worth referencing (Moz).
Backlinks matter for two reasons. First, they influence rankings. Google's ranking algorithm uses backlinks as a trust signal to assess a page's authority and relevance, a concept rooted in PageRank and link equity. Second, they aid discovery (crawling). As you accumulate quality backlinks, search engines find your content faster (Ahrefs). The overall practice of acquiring backlinks is called link building, and it is the central pillar of off-page SEO.
The Six Attributes of a Good Backlink
Ahrefs breaks down a "good backlink" — one likely to move rankings — into the following six attributes. Not every backlink carries the same value.
- Authority — A link from an authoritative site, such as a major news outlet, passes more value. That said, the more outbound links a single page has, the more the authority each link passes is diluted.
- Relevance — A link from a topically related site is worth more. For a plumber's site, a link from a boiler-installation page is more meaningful than one from a page about cats.
- Anchor text — The clickable link text is a clue Google uses to understand the linked page's topic. But an excess of anchors that exactly match your target keyword can look like manipulation.
- Placement — A link in a high-visibility spot, such as the middle of the body content, tends to pass more value than one buried in a footer or sidebar.
- Destination — Because Google ranks pages rather than sites, ideally the link should point to the exact page you want to rank.
- Dofollow — Links carrying a nofollow attribute usually don't affect rankings, so prioritize dofollow links.
To judge quality, look at the linking domain's authority metric (Ahrefs' Domain Rating) and its traffic, alongside how many unique domains link to it (its referring-domain count).
Dofollow vs. Nofollow
A link's rel attribute tells search engines how to treat that link. Google's official documentation (Search Central) makes the following recommendations. Since 2019, nofollow has been treated as a "hint" rather than a "directive."
| Aspect | Dofollow (default) | Nofollow family |
|---|---|---|
| rel attribute | None (no markup needed) | rel="nofollow" / "sponsored" / "ugc" |
| Passes authority | Yes (contributes to rankings) | Generally does not |
| Google handling (2019+) | Crawled and evaluated | Used as a hint, generally not followed |
| Primary use | Ordinary links that vouch for or recommend | Ads/paid, user-generated (comments, forums), links you don't endorse |
| SEO priority | Acquire first | Pursue secondarily when relevance and authority are high |
Google's three qualifying attributes serve distinct purposes. Use rel="sponsored" for advertising and paid links, rel="ugc" for user-generated content links such as comments and forum posts, and rel="nofollow" for other links where you don't want to associate with or have Google crawl the target. You can also combine multiple values with a space or comma (for example, rel="ugc nofollow").
Good Backlinks vs. Backlinks to Avoid
Bad backlinks not only fail to help — when enough of them pile up, they can drag down rankings or trigger a manual action. Here is the contrast Ahrefs lays out.
| Good backlinks (pursue) | Backlinks to avoid |
|---|---|
| Editorial citations within a reputable site's body content | Paid links bought with money or goods |
| Natural recommendations from topically related sites | PBNs (private blog networks) used to manipulate rankings |
| Quality links from guest posting and relationship building | Excessive reciprocal link exchanges |
| Listings in trusted business directories | Links mass-produced by automation software |
| A natural profile built from varied anchor text | Forum/comment spam links and bulk low-quality directory listings |
Although it is not a term Google uses, manipulative links that commonly hurt rankings are often called "toxic" backlinks. Ahrefs notes that a single low-quality link is rarely a threat; the problem arises when a large volume of spam links accumulates. If you have suspicious links and worry about a manual action, you can ask Google to ignore them via the disavow tool.
How to Get Backlinks
Ahrefs sorts backlink acquisition into four categories. The higher up the list, the safer and generally more valuable the approach.
- Earn — Create valuable content so people link to it on their own. Data studies, calculators, and guides are classic "link bait."
- Ask — Pitch links to site owners through guest blogging, broken link building, the skyscraper technique, reclaiming unlinked brand mentions, and similar outreach.
- Add — Add your link where you can register it directly, such as relevant local directories. It is easy, but overdoing it can look like spam.
- Buy — Buying links violates Google's policies and carries a high penalty risk, so it is not recommended.
Do Backlinks Still Matter?
Debate flared after Google's Gary Illyes remarked at a conference in April 2024 that "links matter less than they used to." In response, research by Ahrefs' Patrick Stox confirmed the following: links still correlate with rankings, though the correlation is weak overall, and it grows stronger for higher-volume (more competitive) queries. Moreover, external backlinks correlate with rankings far more strongly than internal links, which suggests Google places greater weight on external links. The takeaway is that backlinks remain an important signal, especially for competitive keywords.
Action Checklist
- Use the "Links" report in Google Search Console or a backlink analysis tool to review your site's referring domains and anchor text distribution.
- When pursuing new links, evaluate their value against the six attributes (authority, relevance, anchor, placement, destination, dofollow).
- Mark advertising and affiliate links with
rel="sponsored"and user comment/UGC links withrel="ugc"accurately. - Keep a natural anchor text mix so that anchors exactly matching your target keyword aren't overrepresented.
- Avoid bought, swapped, and PBN links, and consider disavowing spam links if you're concerned about a manual action.