Link Building and Backlinks: The Complete Guide

Link building is the practice of earning links from other websites to your own, and it is still one of the strongest signals Google uses to decide which pages deserve to rank. Each incoming link — called a backlink — works like a recommendation: when a trusted site points to a page, it passes along a measure of credibility. This page is the starting point for everything on this site about earning links. It explains what link building and backlinks really are, how a link passes authority through Google’s PageRank system, why search engines rely on links at all, and why modern SEO rewards a handful of excellent links far more than thousands of weak ones. From here you can branch out into detailed guides on every sub-topic.

On this page:

• What is link building?
• What are backlinks?
• How backlinks pass authority (PageRank)
• Why Google uses links to rank pages
• Types of backlinks and link attributes
• Link building vs. link earning
• The modern reality: quality over quantity
• How to start link building
• How much does link building cost?
• Common link building mistakes
• Who should invest in link building?
• Glossary, sources and FAQ

What is link building?

Link building is the process of getting other websites to place links that point to your website, with the goal of improving your visibility in search engines. It sits under the umbrella of “off-page SEO” — the work you do away from your own pages to build a site’s reputation — as opposed to “on-page SEO,” which covers the content and technical setup of the pages themselves.

In practice, link building ranges from publishing content that is good enough for others to cite naturally, to actively reaching out to publishers, journalists, bloggers and site owners to earn a mention. The common thread is that a third party chooses to link to you. That editorial choice — someone deciding your page is worth pointing readers to — is exactly what makes a link valuable. If you want the full case for why this work matters, see our guide to why link building matters.

What are backlinks?

A backlink is a link on one website that points to a page on a different website. If Site A includes a clickable link to a page on Site B, then Site B has earned one backlink from Site A. Backlinks are also called inbound links or incoming links, and search engines treat each one as a signal that the destination page is worth knowing about.

The anatomy of a backlink

Every backlink is made up of a few parts, and each part changes how much the link is worth:

• Source page — the page the link lives on. Its own authority and topical relevance strongly affect the link’s value.
• Destination URL — the exact page being linked to on your site.
• Anchor text — the visible, clickable words of the link. Anchor text gives search engines context about the destination; getting the balance right is a topic on its own, covered in our guide to anchor text optimization.
• Rel attribute — an optional tag such as nofollow, sponsored or ugc that tells search engines how to treat the link (explained below).
• Placement and context — a link inside the main body of relevant content typically carries more weight than one buried in a footer or sidebar.

For a deeper look at the different formats — editorial, guest-post, directory, niche-edit and more — read our breakdown of the types of backlinks and the situations each one fits.

How backlinks pass authority: PageRank explained

Backlinks pass authority through a model Google calls PageRank, which treats every link as a vote of confidence from one page to another. When a page that Google already trusts links to your page, a share of that trust — often described as “link equity” or “link juice” — flows across the link to you. Collect enough of these votes from credible sources and your pages become easier to rank.

Where PageRank came from

PageRank was created by Google co-founders Larry Page and Sergey Brin while they were graduate students at Stanford University. Their 1998 paper, “The Anatomy of a Large-Scale Hypertextual Web Search Engine,” argued that the web’s link structure encodes human judgements about quality: a page linked to by many important pages is itself probably important. In other words, links act like academic citations — the more (and the better) the citations, the more authoritative the work is assumed to be. That single idea is what made Google’s results dramatically better than the keyword-only search engines of the day.

How authority flows through a link

The flow of authority across a single backlink can be pictured as a short chain, from a trusted source page to your page:

One important nuance: the equity a page can pass is shared among all the links on it. A page that links out to 3 sites passes more concentrated authority per link than one that links out to 50. This is why a single link from a focused, authoritative page can outperform dozens of links from cluttered, low-value pages.

Why not all links are equal

Two backlinks are rarely worth the same amount. The main factors that decide a link’s value are:

• Authority of the source — links from established, trusted sites pass more equity.
• Topical relevance — a link from a site in your subject area counts for more than one from an unrelated site.
• Editorial context — a link placed naturally within relevant content beats a paid or automated placement.
• Link attribute — a standard “followed” link passes equity; nofollow, sponsored and ugc links generally do not (see below).
• Placement — main-content links tend to carry more weight than footer or sidebar links.

Why Google uses links to rank pages

Google uses links because they are one of the hardest signals for a site owner to fake honestly, and because they reveal what real people find useful. A search engine cannot personally read every page and judge its quality, but it can observe which pages the rest of the web chooses to reference. Links serve three jobs at once:

• Discovery — crawlers follow links to find new pages and revisit updated ones.
• Authority — the quantity and quality of links help estimate how trustworthy a page is.
• Relevance — the anchor text and surrounding content signal what a page is about.

Links are far from the only ranking factor — content quality, user experience and search intent all matter — but they remain central. If you want the current evidence on how much weight they still carry, see our analysis of whether backlinks still matter.

Types of backlinks and link attributes

Backlinks fall into two broad groups based on whether they pass authority: followed links and links with a rel attribute that tells Google to treat them differently. Understanding the attributes is essential because using the wrong one — or failing to use one on a paid link — can breach Google’s guidelines.

• Followed (dofollow) links — the default. No special attribute; these pass PageRank and are the links most SEO work aims to earn.
• rel=”nofollow” — introduced by Google in 2005, this tells search engines not to pass ranking credit through the link. Since March 2020 Google treats it as a “hint” rather than a strict instruction, meaning it may still use the link for discovery.
• rel=”sponsored” — added on 10 September 2019, this marks links created through advertising, sponsorship or any paid arrangement.
• rel=”ugc” — also added on 10 September 2019, this marks links inside user-generated content such as blog comments and forum posts.

You can combine attributes when appropriate (for example, a paid link inside a comment could use rel=”ugc sponsored”). For a full walkthrough of every format and when to pursue it, see the types of backlinks guide.

Link building vs. link earning

Link building and link earning describe two ends of the same spectrum. Link building is proactive: you reach out, pitch, publish guest content or promote assets to actively acquire links. Link earning is passive: you create something genuinely useful — original research, a free tool, a definitive guide — and let people link to it because they want to.

Both are legitimate as long as the link is granted on merit rather than bought for ranking value. In reality, most successful programs blend the two: they build linkable assets worth earning links, then do targeted outreach to make sure the right people see them.

The modern reality: quality over quantity

The single biggest shift in link building is that quality now beats quantity by a wide margin. Buying thousands of cheap links was once effective; today it is a fast route to being ignored or penalised. Two waves of Google enforcement explain why.

Google Penguin and the link spam era

Google launched the Penguin update on 24 April 2012 to target manipulative link schemes — paid links, automated link building and low-quality directories. Penguin devalued spammy links and demoted the sites relying on them. It is no longer a separate update; since 2016 it has been baked into Google’s core algorithm and evaluates links continuously in real time.

SpamBrain and today’s link spam policy

On 14 December 2022, Google rolled out the December 2022 link spam update, the first to use its machine-learning system SpamBrain to detect link spam specifically. Crucially, it targets both sides of a bad link — sites buying links and sites that exist to sell outgoing links. Under Google’s current spam policies, any link acquired through payment, free products or another commercial arrangement must carry rel=”sponsored” or rel=”nofollow”; failing to mark a paid link is itself a violation, separate from the question of link quality.

The practical takeaway is that a few relevant, editorially given links from trusted sites are worth more than a large volume of paid or low-quality ones. If you are considering paid placements, read our guidance on buying backlinks safely before spending anything.

How to start link building

The best way to start is to build something worth linking to, then promote it to the right audiences. These are the core tactics used today, from most to least favoured by SEO professionals:

• Digital PR — creating newsworthy stories, data or surveys and pitching them to journalists. In 2025 surveys it is rated the single most effective link building tactic by roughly half of SEO professionals.
• Guest posting — writing genuinely useful articles for relevant publications in exchange for an editorial link. Still one of the most widely used tactics when quality standards are kept high.
• Broken link building — finding dead links on other sites and suggesting your working page as a replacement.
• Expert commentary — responding to journalist requests (through platforms that connect sources and reporters) to be quoted and cited.
• Linkable assets — original research, calculators, templates and definitive guides that naturally attract links.
• Resource and directory listings — relevant, curated lists and reputable industry directories.

For step-by-step playbooks on each of these, see our deep dive on link building strategies.

How much does link building cost?

There is no fixed price for a backlink, but industry surveys give a useful range. The figures below are third-party survey averages, not fixed rates — costs vary widely by niche, site authority and quality.

Even “free” earned links carry a cost in the time and skill needed to create link-worthy content and pitch it. Budgeting for link building means weighing paid placements against the slower but more durable value of earned links.

Common link building mistakes

Most link building failures come from a small set of avoidable errors:

• Chasing volume over quality — buying large batches of cheap links that add risk, not authority.
• Over-optimised anchor text — using the same exact-match keyword as anchor text again and again, which looks manipulative.
• Ignoring relevance — gathering links from unrelated sites that pass little topical value.
• Unmarked paid links — buying followed links without rel=”sponsored” or rel=”nofollow,” a direct policy violation.
• Private blog networks and mass link exchanges — schemes that SpamBrain is specifically designed to catch.
• No content foundation — trying to build links to thin pages that give no one a reason to link.

Who should invest in link building?

Link building matters most for sites competing in crowded search results, new domains that have not yet built trust, and businesses whose customers research online before buying. E-commerce stores, service providers and content publishers all benefit when their pages earn authority faster than rivals’.

Local businesses have their own playbook, since local relevance and Canadian sources carry extra weight — our guide to link building in Canada covers that in detail. Link building matters less for pages with no competition or purely transactional intent, where content and technical health may move the needle more. To explore every guide in one place, start from the backlinkscanada.ca homepage.

Frequently Asked Questions (FAQ)

What is the difference between link building and backlinks?

A backlink is the link itself — a link on another website pointing to your page. Link building is the ongoing activity of earning those backlinks. Put simply, backlinks are the result, and link building is the work that produces them.

Do backlinks still matter for SEO in 2025?

Yes. Backlinks remain one of Google’s core ranking signals, though their role has shifted toward quality and relevance rather than raw numbers. A few authoritative, editorially given links now outperform large volumes of low-quality ones.

Is buying backlinks against Google’s rules?

Buying links that pass ranking value is against Google’s spam policies. If a link is paid for, it must carry rel=”sponsored” or rel=”nofollow” so it does not pass authority. Unmarked paid links can lead to a loss of rankings.

How many backlinks do I need to rank?

There is no fixed number. The right amount depends on how competitive your keyword is and how strong your competitors’ link profiles are. Quality, relevance and diversity of referring domains matter far more than a specific count.

How long does link building take to work?

Link building is a long-term investment. It can take several weeks to a few months for new links to be crawled, evaluated and reflected in rankings, and competitive niches take longer. Consistent, quality-focused effort compounds over time.