Back links and SEO: how link value is decided and how to earn links that count

A back link is a link on somebody else's website that points to yours. Search engines read links as evidence: if independent sites keep pointing at a page, that page is more likely to deserve attention for the subject it covers. Link value is not equal. It is decided by five things: how relevant the linking site is to your subject, where on the page the link sits, how independent the link is, what the surrounding text says, and whether a human chose to place it. A single editorial link from a publication your buyers read can outweigh several hundred directory and footer links, and most of the links a site accumulates carry close to no weight at all.

This page covers how link value is assessed and how to earn links that hold up. For the crawling and indexing side of search, see a page on site health and crawl access.

What a link actually passes

Two separate things travel along a link. The first is authority, the accumulated trust a search engine assigns to a site and distributes through the links it publishes. The second is context: the anchor text, the sentence around it and the subject of the host page all tell a search engine what your page is about. A link reading "a guide to flat roof membranes" tells a search engine far more than a sidebar link saying "visit website".

A third thing matters more than either, and it gets forgotten in link building programmes: a link on a page that real buyers read sends real buyers.

The five factors that set a link's worth

Factor	What raises value	How to check it
Topical relevance	The linking site covers your subject or serves your buyers	Read the site's last ten articles. Would your customer read any of them?
Placement	Inside the body copy, in a paragraph about your subject	Open the page. A link in a footer, sidebar, author bio or long link list is worth little
Independence	Nobody paid for it, swapped for it or asked for it as a favour	Check for a sponsored or partner label, and whether the same site links to all your competitors too
Anchor and context	Descriptive anchor text, surrounded by relevant copy	Read the sentence containing the link out loud. It should describe the page
Reach of the host page	The page itself attracts readers and has links of its own	Look at whether that single page ranks for anything or gets shared

Domain level scores sold by tools are useful for sorting a long list quickly. They are third party estimates rather than signals a search engine uses, so treat a high score as a reason to look at a site, not as a reason to want a link from it.

The links that do nothing

A large part of most link profiles is inert. Low value patterns include site wide footer links, links from pages that exist only to hold links, mass submitted business directories outside your country or industry, comment and forum signature links, links from sites with no editorial standard that publish anything sent to them, and reciprocal exchanges arranged in bulk.

Google's spam policies name link schemes directly: buying or selling links for ranking purposes, excessive exchanges and large scale guest posting with keyword rich anchors are treated as violations. Any provider promising a fixed number of links per month at a fixed price is selling volume from one of those patterns. Hold the line on this. Google also states plainly that nobody can guarantee a number one ranking, so a seller who promises one is contradicting the search engine they claim to understand.

Four sources that keep producing links

Repeatable link earning comes down to publishing something a writer has a reason to cite.

• Original data. Survey your own customers, aggregate anonymised numbers from your own operations, or collect public records nobody has tabulated. A number with a method behind it gets cited for years, and each citation is an editorial link inside body copy.
• Expert commentary on request. Journalists and trade editors need named sources with a view. Answer quickly, answer specifically, and give a quote they can publish without editing. Speed wins these more often than seniority does.
• A free tool or template. A calculator, a checklist, a sample contract or a working spreadsheet gets recommended inside articles about the task it performs, because the writer needs something to point the reader at.
• Being present where your category is listed. Industry bodies, accreditation registers, supplier lists, local chambers, software marketplaces and association directories. These are narrow, relevant and real, and buyers use them.

Two more sources pay well and look like nothing: fixing links you already earned, which means finding pages that mention your brand with no link and asking for one, and co-authored work with partners, suppliers and customers, where the link follows a real project.

Anchor text, done sensibly

Write the anchor as a human describing the destination. A healthy profile is mostly brand names, bare URLs and natural phrases, with descriptive keyword anchors appearing where they fit the sentence. If you control the anchor on dozens of links and they all read the same way, the pattern is visible, and it reads as placed rather than earned. Where you are asked for preferred anchor text, give a short phrase that matches the page title and let the writer adapt it.

Auditing the profile you have

Run this once, then every quarter so you are working from current data.

• Export your inbound links from Search Console, which shows what the search engine itself recorded, plus one commercial index for breadth.
• Group by linking domain, not by link. One site with four hundred links is one relationship.
• Sort by whether a buyer would ever read that site. Keep the ones that pass and ignore the inert ones.
• Check that your most valuable pages have internal links pointing at them from your navigation and related articles. Internal linking decides how the authority you have already earned gets distributed, and it is entirely under your control.
• List every inbound link that lands on a 404 or a redirect chain and fix the destination.
• Note which competitors hold relevant links you do not. Those sites already accept content on your subject, which makes them the shortest route to a comparable link.

Disavowing links is rarely the right move. Google discounts most low quality links on its own, and the disavow file exists mainly for sites with a manual action or a history of paid link buying.

A sequence that works for a small site

Claim the relevant category listings and association entries first, because they are quick and buyers check them. Publish one piece of original data a quarter and take it to the ten writers who cover your subject by name. Then run a monthly pass over brand mentions and broken inbound links. Three activities, sustainable by one person, and the profile it builds reads as earned, because it was.

How many back links do I need to rank?

There is no threshold. Judge it by comparison: look at the pages currently ranking for your target query, count the independent, topically relevant sites linking to each of those specific pages, and treat that as the bar for that query. For many commercial queries the number is in single figures, and relevance does more work than count.

Do nofollow links have any value?

Yes. Google treats the nofollow, sponsored and ugc attributes as hints rather than strict instructions, so a nofollow link from a strong relevant publication still contributes. More importantly it still sends readers, it still gets seen by people who write about your subject, and it still appears in the sources that AI assistants read.

Is buying links worth it?

No. It is a named violation of Google's spam policies, the links are usually placed on sites that sell to everyone, and the pattern is detectable because the same inventory shows up across hundreds of buyers. Money spent on original research produces links nobody can take away from you.

How long before a new link affects rankings?

The link has to be crawled first, which takes days to weeks depending on how often the host page is visited. Movement usually shows over weeks rather than days, and it shows most clearly on pages that were already close to the first page.

Should I use a link building agency?

Use one that reports placements by name before you pay, works on relevance rather than monthly quotas, and can show you the article a link would sit inside. Ask for the last ten placements they made for a client in any industry. If the answer is a volume figure rather than ten URLs you can open, keep looking.

Who else is reading the links you earn

A backlink report counts links for ranking. The same pages that link to you are also what an assistant reads when a buyer asks it to recommend a company like yours, and what those pages say about you is what gets repeated. A link with a clear description of what you do is worth more here than one in a footer.

Ask ChatGPT, Gemini and Perplexity for providers in your category, then check which of your best links sit on the pages they cite and which sit nowhere they look. Because AI Knows Us lists the sources behind each answer, it gives you a second way to read your link profile.