They are often seen as the most powerful way to rank a site.

But not every link is created equal.

Over time, the search engines have adapted their algorithms to account for links in different ways, narrowing their use for determining the suitability of a webpage as an answer to a search query.

In this post, you will learn what makes a high-quality link, where to find opportunities to build them, and how to evaluate whether a link is worth the budget and effort to get it.

How Do Search Engines Use Links?

Search engines use links pointing to a webpage to both discover its existence and also determine information about it.

Google mentions in its help documentation,

“Google interprets a link from page A to page B as a vote by page A for page B. Votes cast by pages that are themselves “important” weigh more heavily and help to make other pages “important.”

Bing states in its Webmaster Help and How-To guide,

“Bing prefers to see links built organically. This essentially means the links are built by people linking to your content because they find value in your content. This is an important signal to a search engine because it is seen as a vote of confidence in the content.”

What Is Valuable About a Link?

We know that Google uses links like votes.

A link from a well-regarded website will have more clout than a lesser-regarded website.

Authority

This is often discussed as “authority.”

Many SEO tools will try to assign an authority metric to a website or webpage in an attempt to quantify the value of a link from them.

An authoritative webpage linking to your webpage can be a strong signal that it is itself an authoritative source.

In essence, an authoritative website is one that is considered by the search engines to be a reputable source of information about a subject – an authority in it.

Google will, in part, look at that site’s backlinks to determine its expertise and trustworthiness in a subject.

For instance, a website is considered an expert in interior design. It links to a lesser-known website about interior design.

The website by an expert in interior design is confident enough in the content of the lesser-known site that it’s willing to send its visitors there.

That’s a good, impartial way for the search engines to determine the reputation of a site and its authority on a subject.

Relevance

Authority isn’t everything, however.

Think of it like this… you’re going on holiday to a city you’ve never visited.

Who would you rather ask for restaurant recommendations: your friend who lives in the city, or a tour guide for a city 5 hours away from it?

Your friend who lives in the city is likely more of a relevant source of information on the restaurants in the area than the tour guide who doesn’t serve that area.

You might perceive a tour guide to be more knowledgeable about good restaurants, but not if it’s not their area of expertise.

In a similar way, the search engines will understand the value of a website in your industry linking to your webpage.

A website that reviews restaurants will be considered a more relevant source of information about restaurants than a local community group who had an outing to a restaurant.

Both sites may have a page talking about the “best sushi restaurant in New York,” but the restaurant review website will be more relevant in helping the search engines determine what to serve as an answer for “sushi restaurant in New York.”

Authority & Relevance

The best source of a link is a website that is both considered authoritative and relevant to your website.

What Makes a Link Low-Quality?

If we think of a quality link as one that is both relevant and authoritative, then it makes sense that the lowest quality link is one that is both irrelevant and not authoritative.

These sorts of links are usually easy to come by and can be self-created or requested.

For instance, a website that allows anyone to submit a link is unlikely to have highly curated content that would lend it to being authoritative.

The fact that anyone can add a link to the site means it isn’t likely to be particularly relevant to one industry or niche.

Links to your site from a website like this will be low-quality and generally useless.

At best, these links might have a little positive impact on your search rankings but at worst they could be perceived as part of a manipulative linking scheme.

Google has strict guidelines on what is considered a manipulative link.

You might want to familiarize yourself with Bing and Yandex’s definitions, too.

A Word About Paid Links

We all know by now that paying for links to aid rankings is against the guidelines of most big search engines.

In a best-case scenario, the link won’t be identified as having been paid for and you won’t see a penalty from it.

However, if Google detects that you’ve acquired links from websites that sell links, you may find the webpage it links to penalized.

There are legitimate reasons why links might be placed on websites for a fee.

It’s common practice to utilize banner advertising and affiliate marketing on the internet, for example.

In these instances, Google recommends that webmasters declare the links to be sponsored using the rel=”sponsored” attribute.

This indicates to Googlebots that the link is one that has been paid for and is not to be used for calculating PageRank.

These sorts of links have their own value for marketing and should not be discounted simply because they will not necessarily aid in search rankings.

A Word About NoFollow Links

Before Google introduced the use of the rel=”sponsored” attribute, it and other search engines were using the rel=”nofollow” attribute.

Putting a rel=”nofollow” attribute into the HTML for a link shows the search bots that they shouldn’t go to the destination of that link.

This is used by publishers to stop the search engines from visiting the page and ascribing any benefit of the link.

So, if a high-quality page links to your webpage with a link contain a rel=”nofollow” attribute, you won’t see any ranking benefit of that link.

Google announced recently that this attribute is a hint and therefore it might ignore it.

On the whole, this essentially makes a “nofollow” link useless for SEO link-building purposes as link equity will not pass through the link.

However, if people are following the link and discovering your webpage, I would argue it’s not useless at all!

What Do High-Quality Links Looks Like?

Low-quality links are usually those that are either:

• Irrelevant in helping the search engines determine your site’s authority on a subject.
• Or actually harmful.

I’m not addressing link penalties here, or even the sorts of link-building practices that will land you in hot water. For more information on that, see Chuck Price’s article on manual actions.

The low-quality links we’re talking about here are ones that you may well be going after but aren’t benefiting your site.

High-quality links are the Holy Grail of link-building.

They’re the links you show off in your “Team Wins” Slack channel and on Twitter.

They are hard to earn.

I also want to show you some “medium-quality” links.

These are the types of links that are good to get but perhaps won’t move the needle as much as you would like.

They form a part of a healthy backlink profile but aren’t worth your whole content marketing budget to land.

Low Quality: Low Authority/Low Relevance

The sorts of links you are likely to gain that are low-quality and low-relevance are ones that require no real effort to get.

For example, simply sourcing the links and asking for them or, in some cases, adding the link yourself.

Open Directories

These directory sites are very obviously low quality when you visit them. Typically they only offer one service – advertise your website here!

You do not need to pay for a link and everyone and their dog has taken advantage of this.

There will be links from websites in all sorts of industries with very little rhyme or reason as to why this directory exists.

Do note, however, that there are reputable local business directories that can help with verifying your business’s physical address and contact details—Yelp, for instance.

These listings are useful for local citations but are unlikely to really aid in boosting your site’s rankings.

The difference between reputable local directories and generic open directories is quite obvious when you visit them.

Comment Links

Forums ad blogs can be very relevant to a particular industry.

However, due to the ease with which anyone can add content to a forum page or blog comments, any links in that user-generated content are usually discounted by the search engines.

In recent SEO history, blog and forum comments were easy targets for squeezing in a link to a site.

The search engines became wise to this and started devaluing those links.

Alongside the rel=”sponsored” attribute, Google released rel=”ugc”.

This is a way for webmasters to indicate that the links within their forums are user-generated.

Low Quality: Low Effort & No Follow

Social Media Posts

Most large social media sites will use “no follow” tags on them.

However, Google did recently say that “nofollow” tags would be taken as hints rather than concretely respected.

Despite this, social media sites are not the place to go looking for backlinks to help your rankings.

Although social media sites themselves are often authoritative, they are full of uncurated content.

Businesses can set up their own social media pages with links back to their websites. They can talk about their sites in their posts.

These links are not unbiased. Due to this, they are largely ignored by search engines.

Medium Quality: Low Authority but High Relevancy

Small Industry Blogs

Most industries have a proliferation of blogs. Sites run by companies or individuals who want to share their knowledge and build their profile.

There are some highly relevant, niche blogs that might not be well-known enough to be getting their own authority-metric boosting backlinks.

They are, however, full of decent content and very relevant to the website you are trying to grow.

Small industry blog writers are often less over-run with requests to share content and add links than the well-known ones.

They are, however, keen to write and build community.

A smaller blog featuring your site is still a good reinforcement of your relevance to your industry.

This can help enormously with showing your relevance to search topics associated with that industry.

Small Industry Brands

There will be some staple brands in your industry that aren’t necessarily competitors but are tangentially related.

Think of paper manufacturers to your office supply store, for example.

A link from the paper manufacturer showing your store as their distributor can help show your authority in the industry.

Medium Quality: Medium Authority & Medium Low Relevancy

Local News Sites

Your local news site may report on anything to do with your community, or they might be more discerning.

Regardless, doing something considered locally newsworthy can get you featured a lot easier than in a national news website.

These are especially good links to get if you are trying to boost your local SEO efforts.

A link from a website known as a source of reliable local information could help the search engines to see your relevance to that physical area.

High Quality: High Authority but Medium/Low Relevancy

Some sites are extremely authoritative and hard to get a link from. These tend to be beneficial to your SEO efforts.

These sorts of links might not be highly relevant, however.

Although you will see a benefit to your search visibility, it may not help solidify your relevance for particular topics.

National News Sites

There are some national and international newspapers with extremely high authority websites. A link from these sites is worth the effort.

However, journalists are inundated with hundreds of press releases and article ideas every day.

It can be incredibly difficult to get featured, especially with a link.

The best way to get coverage in a national newspaper is to do something newsworthy.

Bringing it to the attention of the site’s journalists might help you get it covered, hopefully with a link back to your site.

High Quality: Medium Authority but High Relevancy

Big Industry Blogs

That website that everyone in the industry goes to for their news; your friends and family may not have heard of it, but your colleagues definitely have.

It’s likely to be a medium authority site according to authority metrics but it’s a leader in your industry.

It’s also very relevant to the website you’re promoting.

A link from a site like this will go a long way in showing your site’s expertise.

High Quality: High Authority & High Relevancy

Big Industry Brands

These are household names; the companies everyone in your industry (and possibly their families) know of.

These links are likely to be medium to high authority according to the tools but definitely leaders in your industry.

If you are linked to as a supplier or distributor, or even just mentioned in a favorable review, you are likely to see the ranking benefit.

Conclusion

A wide and varied link profile is good for SEO.

If you are actively looking to increase links to your site in an organic manner, it’s imperative you know how to generate high-quality links.

Don’t waste your time going for easy links on unrelated and low-quality sites.

Instead, focus your energy and budget on creating truly newsworthy content and bringing it to the attention of authoritative and relevant publishers.

More Resources:

Search Engine Journal