What are Backlinks? SEO Guide for Beginners

Learn what backlinks mean in SEO, why they matter, and how to use them to improve your search rankings.

Backlinks are links from other websites that point to your website. When another site links to one of your pages, that counts as a backlink. Search engines treat these links as votes of confidence. The more quality backlinks your site earns, the more authoritative Google considers it, which directly impacts where you rank in search results.

Why Backlinks Matter for SEO

Backlinks have been one of Google's top ranking signals since the beginning. PageRank was one of Google's core ranking systems at launch, built on the idea that pages with more quality inbound links are more valuable. Google confirms PageRank remains part of its core ranking systems today, though how it works has evolved a lot since the original 1998 algorithm.

In an analysis of 11.8 million Google search results, Backlinko (working with Ahrefs as its data partner) found a clear correlation between links and rankings. The number one result had on average 3.8x more backlinks than the pages ranking in positions 2 through 10, and 3x more referring domains (the count of unique websites linking to a page). The same study concluded that earning links from a diverse group of domains matters more than piling up links from a single source.

But not all backlinks are equal. A single link from a trusted, relevant site like a major industry publication can move the needle more than 100 links from random, low-quality blogs. Google evaluates the authority of the linking site, the relevance of the content, the anchor text used, and whether the link is dofollow or nofollow.

Backlinks also help Google discover new pages faster. Google's documentation states it uses links both as a relevancy signal and to find new pages to crawl. When Googlebot crawls a high-authority site and finds a crawlable link to your content, it can follow that link and crawl your page. One caveat from Google's link best practices: a link is generally only crawlable if it is an <a> element with an href attribute, so links built only with JavaScript click handlers may not be discovered this way.

How Backlinks Work

When Site A links to Site B, Google interprets that as Site A vouching for Site B's content. The value passed through that link is called "link equity" or sometimes "link juice." Several factors determine how much equity a backlink passes.

Authority of the linking page matters most. A link from a page that itself has many backlinks passes more value than a link from a page nobody links to.

Relevance plays a huge role. A link from a cooking blog to your recipe site is more valuable than a link from a tech blog to your recipe site. Google uses topical relevance to weigh the value of links.

Anchor text gives Google context about what the linked page is about. If someone links to you with the anchor text "best project management tools," Google takes that as a signal about your page's topic.

Followed vs qualified links determines whether link equity is passed. A normal link with no rel attribute (often called "dofollow") can pass ranking value. Qualified links use a rel attribute to tell Google how to treat them. Google supports three values: rel="nofollow" (you do not want to endorse or pass credit to the page), rel="sponsored" (the link is an advertisement or paid placement), and rel="ugc" (the link sits inside user-generated content like comments or forum posts). Since March 2020 Google treats all three as hints rather than strict directives, so they generally are not followed but Google may still consider them when deciding what to crawl and index. Links from social media, forums, and Wikipedia are typically qualified with one of these attributes.

How to Build Backlinks for Your Site

Create genuinely link-worthy content - Original research, comprehensive guides, free tools, and unique data visualizations naturally attract links. If your content is the best resource on a topic, other sites will reference it. This is the foundation of sustainable link building.
Write guest posts on reputable industry sites - Reach out to blogs and publications in your niche and offer to write high-quality articles. Most will let you include 1-2 links back to your site in the author bio or naturally within the content.

Use the broken link building technique - Find broken links on relevant websites using tools like Ahrefs or Check My Links browser extension. Email the site owner, let them know about the broken link, and suggest your content as a replacement. This works because you are helping them fix a problem.

Leverage digital PR and data-driven content - Create surveys, run studies, or compile industry statistics that journalists and bloggers will want to cite. Reach out to reporters through platforms like HARO (Help A Reporter Out) or Connectively. A single piece of data-driven content can generate dozens of high-authority links.

Reclaim unlinked brand mentions - Use tools like Google Alerts or Ahrefs Content Explorer to find mentions of your brand that do not include a link. Email the site and politely ask them to add one. Since they already mentioned you, the conversion rate on these requests is high.

Common Mistakes to Avoid

Buying links from link farms or PBNs: Google's spam policies define link spam as creating links primarily to manipulate rankings, and they explicitly list exchanging money for links among the prohibited tactics. The short-term ranking boost is never worth the risk of a manual action that tanks your entire domain. If you do pay for a link for legitimate advertising reasons, Google's own guidance is to mark it with rel="sponsored" or rel="nofollow" so it does not pass ranking credit.

Prioritizing quantity over quality: 50 backlinks from spammy directories hurt more than they help. Focus on earning links from sites that have real traffic, relevant content, and genuine authority.

Using the same anchor text for every link: If every backlink to your page uses the exact same anchor text, it looks manipulative. A natural link profile has varied anchor text including branded terms, naked URLs, and generic phrases like "click here."

Key Takeaways

Backlinks are links from other sites to yours, and they remain one of Google's strongest ranking signals
Quality matters far more than quantity. One authoritative, relevant link outweighs dozens of low-quality ones
The most sustainable approach combines creating link-worthy content with proactive outreach strategies
Monitor your backlink profile regularly using tools like Ahrefs, Semrush, or Google Search Console to catch toxic links early

In Practice

Say a SaaS company sponsors a roundup post on an industry blog and the blog owner agrees to link back. Because money changed hands, that link must be qualified so it does not pass ranking credit, otherwise both sites risk a link spam action. The correct markup follows Google's outbound link guidance exactly.

Paid placement, marked as sponsored:

<a rel="sponsored" href="https://yoursaas.com/pricing">Acme Project Tracker</a>

A link dropped by a reader in a blog comment, which should be marked as user-generated content:

<a rel="ugc" href="https://reader-blog.example/post">my own writeup</a>

A link you want to reference but neither endorse nor pass credit to:

<a rel="nofollow" href="https://example.com/source">original claim</a>

You can combine values when both apply, for example a sponsored link inside a comment thread:

<a rel="sponsored ugc" href="https://example.com">offer</a>

Contrast that with an editorial backlink you earned, where another site cited your original research on its own. That link carries no rel attribute and is free to pass ranking value, which is exactly the kind of link the rest of this guide tells you how to earn:

<a href="https://yoursaas.com/research/2026-report">2026 productivity report</a>

What Is Anchor Text covers the visible link text that gives Google context about a backlink's target.
What Is DoFollow explains the default followed link that can pass ranking value.
What Is NoFollow details the rel attribute that asks Google not to pass credit.
What Is Domain Authority describes the third-party authority score often used to judge a linking site's strength.
What Are Toxic Links shows how to spot and clean up the spammy backlinks this guide warns against.