que es el linkbuilding

What Is Link Building: The Complete Guide to Earning Backlinks

Link building is the SEO strategy of getting other websites to link to yours in order to build your authority in Google’s eyes. It is one of the most important ranking factors and also one of the hardest to get right.

A good link building strategy does not just improve your organic rankings; it strengthens your presence in Google’s AI Overviews, where sites with higher domain authority have an advantage when it comes to being cited as a source.

In this guide we explain what link building is, what types of links exist, how to earn them safely and which mistakes to avoid. Practical information from our SEO agency in Barcelona, where link building is a core part of every strategy.

What you will learn in this guide

  • What link building is: the definition and why it is key to SEO
  • Types of link: dofollow, nofollow, natural, manual and profile links
  • Effective strategies: how to earn quality links without taking risks
  • Mistakes to avoid: the link building practices Google penalises

Contents

What is link building?

Link building is an off-page SEO strategy aimed at getting other websites to link to your site. These external links, known as backlinks, work like votes of confidence in Google’s eyes: the more quality links your site receives, the more authority it has and the better it ranks.

Think of backlinks as professional recommendations. If recognised experts in your field recommend your content by linking to it, Google reads that as a sign your site offers valuable, relevant information. That trust signal is one of the most important ranking factors in the algorithm, alongside on-page optimisation and technical SEO.

Link building can be natural (when other sites link to your content spontaneously because they find it useful) or proactive (when you run specific campaigns to earn those links). A complete SEO strategy combines both: creating excellent content that attracts natural links, and adding outreach to speed up results.

Why link building matters for SEO

Backlinks are fundamental because they are one of the three pillars of SEO, alongside content and technical optimisation. When an authoritative site links to yours, it passes on part of its reputation, which Google reads as a quality signal.

These are the concrete benefits link building brings to your digital strategy:

  • Greater domain authority: Quality backlinks raise your Domain Authority (DA), a metric that predicts your ability to rank
  • Better rankings in Google: Pages with more quality backlinks tend to hold the top positions
  • Referral traffic: People who click those links arrive straight on your site
  • Faster indexing: Google discovers new content by following links, so more backlinks means quicker indexing
  • More brand visibility: Being mentioned on relevant sites raises your profile in the industry

A Backlinko study of more than 11 million search results confirmed a direct correlation between the number of unique domains linking to a page and its position in Google. Pages in first place have on average 3.8 times more backlinks than positions 2-10.

Types of link: dofollow vs nofollow

Not every link carries the same SEO value. It is essential to understand the difference between the two main types:

Dofollow links

These are standard links that pass authority (link juice) from one page to another. When a site links to you with a dofollow link, it is telling Google: “I trust this content and I recommend it”. These are the most valuable links in your strategy because they affect your rankings directly.

Nofollow links

These carry the rel=”nofollow” attribute, telling Google not to pass authority. They are common in blog comments, forums and sponsored links. Although they do not pass authority directly, they are still useful: they bring referral traffic, they diversify your link profile (something Google likes) and they raise your brand’s visibility.

Other link attributes

Google introduced extra attributes to classify links more precisely:

  • rel=”sponsored”: For paid or sponsored links
  • rel=”ugc”: For links in user-generated content (comments, forums)

A natural link building strategy should include a mix of dofollow and nofollow links. A profile that is 100% dofollow can look artificial to Google.

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What makes a backlink a quality one?

Not all backlinks are worth the same. Google weighs a number of factors to determine a link’s quality and its impact on your rankings:

  • The authority of the linking domain: A link from a national newspaper or the BBC carries far more weight than one from a brand new blog. Tools such as Ahrefs or Moz give authority scores (DR, DA) that help you judge this
  • Topical relevance: A link from a site in your own industry is more valuable than one from a completely different field. If you run a sports shop, a link from a fitness magazine is worth more than one from a cookery blog
  • Where the link sits: Links inside the main content (editorial links) are worth more than links in sidebars, footers or navigation menus
  • Anchor text: The clickable text helps Google understand what the linked page is about. It should be natural and varied, avoiding over-optimisation
  • The site’s traffic: Links from sites with real traffic are worth more than links from abandoned sites with no visitors
  • The link’s context: A link surrounded by relevant, quality content is worth more than an isolated one

The golden rule: always put quality ahead of quantity. A single link from a major media outlet can have more impact than 100 links from low-quality directories.

Link building strategies that work

There are many techniques for earning quality backlinks. The most effective and sustainable over the long term are:

Guest posting

This means writing articles for other blogs or publications in your field in exchange for a link back to your site. It is one of the most effective strategies because you give the publisher real value. To find opportunities, search Google for terms like “write for us + your industry” or look at where your competitors publish.

Link baiting

Create content so valuable that others want to link to it naturally: original studies with your own data, infographics, free tools, exhaustive guides or unique resources. Content that earns links usually solves a specific problem or provides information that exists nowhere else.

Broken link building

Find broken links on sites in your field (pages returning a 404) and contact the webmaster offering your content as a replacement. Tools like Ahrefs or Check My Links make this easier. It is win-win: you help the site fix a problem and you earn a link.

Unlinked mentions

Monitor mentions of your brand online. When someone mentions you without linking, get in touch politely and ask them to add the link. Tools such as Google Alerts or Mention help you track these opportunities.

Competitor analysis

Study your competitors’ backlink profiles with tools like Ahrefs or SEMrush. Identify which sites link to them and work out how to earn similar links. If a publication has linked to a competitor, it is probably open to linking to similar content in the sector.

Common link building mistakes to avoid

Badly executed link building can seriously damage your rankings. These are the most frequent mistakes to avoid:

  • Buying links in bulk: Google penalises paid link schemes. Link farms and low-quality PBNs (Private Blog Networks) can destroy your rankings. If you do invest in links, be selective and stick to legitimate publications
  • Over-optimised anchor text: If every backlink uses the same anchor text with your main keyword, Google will spot it as manipulation. Vary your anchors: use your brand, URLs, natural phrases and secondary keywords
  • Ignoring relevance: Earning links from sites with nothing to do with your field is a waste of time and can raise flags. Always prioritise topical relevance
  • An unnatural acquisition rate: Going from 0 to 500 backlinks in a week is a clear sign of manipulation. Links should grow gradually and steadily
  • Forgetting internal linking: Links between the pages of your own site matter too. They spread authority and make navigation easier
  • Not monitoring your profile: Toxic backlinks can appear without you looking for them (negative SEO attacks). Review your profile regularly in Google Search Console and use the disavow tool if you need to

Link building tools

Link building is a fundamental part of any serious SEO strategy. It takes knowledge, time and careful execution to avoid penalties and get the most out of it.

At JRC Web we have spent years helping businesses improve their rankings with ethical, effective link building. As an SEO agency in Barcelona, we analyse where you stand, identify opportunities and run campaigns that deliver sustainable results.

Alongside SEO, we offer professional web design so your site not only ranks well but also turns visitors into customers.

Want us to analyse your site’s backlink profile? Get in touch and we will run a free audit with recommendations tailored to your business.

How many backlinks do I need?

To run an effective link building strategy you need tools to analyse backlinks, find opportunities and monitor results:

  • Google Search Console (free): Shows you the sites linking to you, the most-used anchor text and the pages receiving the most links. It is the basic, official starting point
  • Ahrefs: The most complete tool for backlink analysis. It lets you spy on competitors’ links, find broken link opportunities and monitor new and lost links
  • SEMrush: A complete SEO suite including backlink analysis, toxic link audits and built-in outreach
  • Moz Link Explorer: Offers its own metrics such as Domain Authority (DA) and Page Authority (PA), useful for judging potential links
  • Ubersuggest (free with limits): Neil Patel’s accessible alternative for basic backlink and keyword analysis
  • Hunter.io: Essential for finding contact emails when doing guest posting outreach
  • HARO (Help A Reporter Out): A free platform where journalists look for expert sources. Answering queries can earn you links from high-authority publications

For a fuller picture of your SEO situation, we recommend an SEO audit that includes an analysis of your current backlink profile.

Link building for different kinds of project

There is no magic number of backlinks needed to rank. It depends on your industry, the competition and the goals of each page. What matters is not the quantity but the quality and relevance of the links.

To work out how many backlinks you need, analyse your direct competitors:

  • Use Ahrefs or SEMrush to see how many unique domains link to the pages holding the top positions for your target keywords
  • Work out the average number of backlinks across the top 10 results
  • Take that number as your initial benchmark, bearing in mind that quality can make up for quantity

A practical approach: start by earning 1-2 quality backlinks a month. That pace is sustainable, looks natural to Google and lets you build authority steadily. Over time, as your content gains visibility, natural links will complement your proactive work.

How long does link building take to work?

Your link building strategy varies with the type of business and its goals:

Blogs and content projects

Prioritise guest posting, creating linkable content (studies, infographics) and taking an active part in communities in your niche. Networking with other content creators is key to earning natural links and collaborations.

Online stores (e-commerce)

Look for product reviews on specialist blogs, work with influencers in your field and create useful buying guides that others want to link to. Category pages and blog articles are usually better link targets than individual product pages. Good web design makes navigation easier and improves user experience, which indirectly helps you earn links.

Local businesses

Focus on quality local directories, mentions in local media, partnerships with other businesses in the area and sponsorship of local events. Local SEO and consistent NAP citations (Name, Address, Phone) are fundamental for this kind of business.

B2B companies and professional services

Thought leadership content is your best asset. Publish industry studies, speak at events, work with professional associations and look for mentions in the specialist media in your industry.

Trust JRC Web with your link building strategy

Link building is a long-term strategy. Results are not immediate because Google needs time to discover, crawl and evaluate the new links you earn. That process can take anywhere from weeks to several months.

Factors that affect how quickly you see results:

  • Your site’s current authority: If your domain already has some authority, new links take effect faster
  • How competitive your industry is: In highly competitive niches you will need more links and more time to see improvements
  • The quality of the backlinks: Links from high-authority sites have an impact faster than links from new ones
  • Crawl frequency: Google crawls active, authoritative sites more often

As a general guide, expect 3 to 6 months before you see significant results from a consistent link building campaign. Patience is key: the results are cumulative and the long-term impact usually exceeds initial expectations.

Frequently asked questions about link building

Buying low-quality links or links from link farms is risky and can result in Google penalties. Working with legitimate publications through sponsored content (always labelled as such), however, is an accepted practice. The key is to prioritise quality and relevance over quantity.
Costs vary enormously depending on the strategy. Guest posting can run from €50 to €500 per link depending on the authority of the publication. Professional tools such as Ahrefs cost around €99/month. A full campaign managed by an agency can range from €500 to €3,000 a month depending on the scope and how competitive the sector is.
Link building involves proactive work to earn links (outreach, guest posting, partnerships), whereas link earning relies on creating content so valuable that others link to it of their own accord. A complete strategy combines both: excellent content that attracts natural links, backed up by active promotion.
Links from social media are nofollow and do not pass authority directly. They do bring indirect benefits, though: they generate referral traffic, increase the visibility of your content (which can lead to links from other sites) and contribute to the healthy digital presence Google rewards.
Use tools such as Ahrefs, SEMrush or Google Search Console to analyse your backlink profile. Look for links from spam sites, link farms, unrelated adult content sites or penalised domains. To remove them, first try contacting the webmaster to request removal. If they do not reply, use the disavow tool in Google Search Console.

Yes. Domain authority, which is built largely through quality link building, is one of the factors Google weighs when choosing sources for its AI Overviews. A site with good inbound links from relevant places has a better chance of being cited in AI-generated answers than a site with no external authority.

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