The Five Rules for Quality Link Building

First published in 2015, rewritten in 2026 so the advice holds today.

Backlinks are still one of the strongest signals Google uses to work out whether your site deserves to rank. That hasn't changed since we first wrote about this. What has changed is how unforgiving Google is when links look manipulative, and how much easier it now is to spot the difference between a link that was earned and one that was bought or begged for.

If you're running SEO in-house or briefing an agency, it's worth revisiting the basics, because the core judgement calls are the same ones we made a decade ago. A handful of good links still beats a pile of poor ones. The difference now is that Google's systems are far better at telling them apart, and the penalties for getting caught land faster.

The five rules still hold

These were true in 2015 and remain the right way to think about any link before you pursue it:

• Less is more. Five links from sites Google trusts will do more for you than hundreds from sites it doesn't. Large volumes of low-quality links can still drag a site's visibility down rather than up.
• Relevance rules. A link only carries weight if it comes from a site in or near your industry. Links from completely unrelated sites look exactly like what they usually are: paid placements or link swaps.
• Authority matters. A link from a site Google already trusts is worth more than one from an obscure or spammy domain. Third-party metrics such as Ahrefs' Domain Rating or Moz's Domain Authority are a reasonable proxy for this, though neither is Google's own measure.
• Location counts. A link on a page's main body content, next to other credible references, is worth more than one buried in a footer or a long, unmoderated resource list.
• Never overlook traffic. A link that real people actually click is doing its job twice over: it sends visitors and it signals to Google that the placement is genuine.

What's changed since 2015

A few things in the original advice need updating:

• Public PageRank is gone. Google retired the visible PageRank toolbar score in 2016, so "checking a site's page rank" as a quality signal no longer means anything literal. Use a mix of organic traffic estimates, referring domains and editorial reputation instead.
• Penguin is now built into the core algorithm. Since 2016, Google's Penguin system has worked in real time as part of normal ranking, rather than as a periodic update that punished sites after the fact. This means bad links are devalued or flagged much faster than they were in 2015.
• Link attributes matter more. Google introduced rel="sponsored" and rel="ugc" in 2019, alongside the older rel="nofollow". Any paid placement, guest post arrangement or user-generated link should carry the correct attribute. Google treats these as hints, not hard rules, but using them properly is now standard practice and their absence on paid content is an easy red flag for reviewers.
• E-E-A-T is the framing Google now uses. Google's public guidance talks about Experience, Expertise, Authoritativeness and Trust. A link from a site with none of these earns you little, regardless of its domain metrics.

How to vet a link before you chase it

Before agreeing to any placement, ask the same practical questions every time:

1. Would a real reader of this site plausibly click the link?
2. Is the site genuinely relevant to your industry, not just vaguely adjacent?
3. Does the site have a track record Google would recognise as trustworthy?
4. Is the link placed in the main content, not a sidebar, footer or link farm page?
5. If it's paid, sponsored or user-submitted, is it marked as such?

If you can't answer yes to most of these, the link isn't worth having, however cheap or easy it is to get.

Where the effort should go instead

The practical shift since 2015 is less about new rules and more about where the work sits. Cold outreach and directory submissions have largely stopped working. What replaced them is digital PR: creating something genuinely newsworthy, original research, data or a strong opinion piece, and pitching it to journalists and industry sites who link to it because it's useful to their readers, not because you asked nicely. It's slower and harder to scale, but it produces exactly the kind of links Google now rewards: relevant, authoritative, well-placed and capable of sending real traffic.

The judgement calls from 2015 haven't aged badly. What's changed is the tooling Google uses to catch shortcuts, and the speed at which it acts. Treat every link the way you'd treat a piece of coverage: would you be happy explaining it to a journalist, and would a genuine reader click it? If the answer is yes, it's worth having.