On-page optimization is a process of creating content that helps search engines (and users) understand what your website is about. Off-site optimization is about demonstrating to search engines that your content offers value to third parties. And the most important value statement is a backlink.

What’s the difference between a link and a backlink?

Individual documents on the web interconnect via links—they’re the glue that holds the web together. Internal links are links between web pages on the same domain, and they primarily exist to help people navigate the website. External links connect to web pages on other domains and have a wider range of possible intentions.

• Provide wider context to the reader
• Support a claim made in the copy
• Cite or provide a source
• Recommend something
• Add authenticity

In each case, the link is on the page to provide additional value to the reader, so the outgoing link is a valuable asset. It’s key to understand that the link has a direction. When it’s outgoing on the linking webpage, it’s incoming to the target page. Therefore, this is a backlink to the target page.

Search engines recognize that the backlink has value and reward the target URL, interpreting the link as fully intentional; they assume there’s been some level of editorial assessment of the target webpage.

That’s why backlinks that point to your website indicate to search engines that your content has value. In fact, backlinks are one of the most powerful ranking factors. They play a huge role in the success (or failure) of every website when it comes to organic search traffic.

What's backlink authority and how is it determined?

One of the main reasons Google is the dominant search engine is because it was the first to realize the importance of backlinks. When Google launched in 1998, it used a revolutionary algorithm for ranking web pages based on link popularity—meaning a page ranks higher if there are more links to it.

This algorithm, named “PageRank” after Larry Page (co-founder of Google, along with Sergey Brin), doesn’t just compute the number of links a given webpage receives; it also measures the authority of those links.

This means that not all backlinks are equal. Imagine one of the pages on your website has a backlink from 2 web pages on different external domains:

• Page A has 200 backlinks
• Page B has 20 backlinks

If these 2 pages were about the same topic, Page A would likely rank higher than Page B. This is because Page A would be more authoritative due to the fact that it has 10 times as many links.

In terms of these 2 backlinks to your site, the link from Page A is more valuable than the link from Page B because it has a higher authority.

Essentially, the PageRank algorithm assigns an authority value to each webpage based on the quantity and quality of its incoming links.

Exploring a simple link network

PageRank is an iterative algorithm. This means the data gets computed, feeds back into itself, and then needs to be rerun through many iterations before it stabilizes.

This is because the relative authority of all the pages in a given network depend on one another. For example, imagine a network of 4 pages.

• Page A links to Page B and Page C and has a backlink from Page B
• Page B links to Page A and Page D and has backlinks from Page A and Page C
• Page C links to Page B and Page D and has a backlink from Page A
• Page D does not link out but has backlinks from Page B and Page C

In order to calculate the authority passed to Page D, we first need to know the authority of Page B and Page C. But the authority of Page B is dependent on Page A and Page C, and the authority of Page A itself is dependent on Page B.

You can see how even a simple network can become complex quickly. It’s only by iterating through the calculations again and again that the solution presents itself. The math is not that complicated, but the size of the dataset (the trillions of links across the entire internet) and the amount of computation required make it a huge task.

What’s domain authority?

Domain authority describes the mini-network of URLs and links that exist on your own site. As with backlinks from external sites, internal links within your own site also pass authority from one URL to another.

It makes sense that links from big brand websites have more domain authority than links from small local businesses. For example, a link from a page on CNN is valuable because CNN is an authoritative website. Lesser-known websites have less authority.

If your homepage gets backlinks from a local news website, this boosts the authority of your homepage. But since it also links out to other pages on your site, some of this authority distributes to the pages linked to from your homepage. With this authority boost, the authority is also shared among the pages that they link to. So incoming backlinks from external sites eventually trickle through the internal link architecture across your whole site. The closer to the top of the chain, so to speak, the more link authority they receive.

This is how big brands can dominate the market for certain sets of search terms. The power of their domain, and smart internal linking practices, can mean that even brand new pages rank well.

Quantity and quality: When it comes to backlinks, both matter

Although accurately calculating the exact value of link authority is a very opaque and complex task, knowing how PageRank works provides some basic rules of thumb.

• You want to attract as many backlinks as you can.
• It’s better to get backlinks from authoritative websites.
• You can use your intuition to determine if a website looks authoritative.
• Attracting more backlinks will have a positive effect on your entire website.

In short, you want both quality and quantity when it comes to backlinks.

Evaluate backlinks for relevance

The other important factor when it comes to backlinks is relevance. In addition to calculating the authority of a backlink to your website, Google is also looking at the relevance of the link—does the topic of the link, page content, or website match the topic of the link target?

Imagine you have a website that sells musical equipment, and you have a web page selling guitar picks linked to from 3 different websites:

Link 1

• The website is very popular in the music industry.
• The web page that contains the link is about guitars.
• The anchor text used in the link is “Read more here.”

In this case, the anchor text doesn’t pass any relevance signals, but the web page and the website do, making this a relevant link.

Link 2

• The website is very popular in the automotive industry.
• The web page that contains the link to you is about refueling.
• The anchor text used in the link is “Gasoline vs. diesel.”

For Link 2, there are no relevant signals. In fact, the link seems so irrelevant that Google might attach no value to it at all, despite it being from an authoritative website.

Link 3

• The website is not very popular in the guitar equipment industry.
• The web page that contains the link to you is about guitar picks.
• The anchor text used in the link is “Best guitar picks.”

In Link 3's example, the website, web page, and anchor text are all relevant. Despite being on a less authoritative website, this is a valuable link as it passes clear relevance signals.

You can end up with backlinks from many different sources. Some of them are from seemingly irrelevant websites, and in general, these neither help nor hurt you. The links that will help you the most are highly relevant, as this gives a much clearer signal to Google that your site is a good match for a particular topic.

How to gain backlinks

Once you’ve done what you can for on-page optimization, building backlinks to your site is the most valuable thing you can do to improve your rankings.

Unfortunately, it’s one of the most difficult tasks in SEO. To get a link, you need to convince someone else that they can improve a web page on their site by linking to a web page on your site.

It’s inadvisable to email random people and ask them to link to you. Instead, there are more professional best practices to get backlinks to your site.

Link building

Link building is the process of actively acquiring backlinks. It’s a niche specialty of SEO that takes a lot of practice.

When you’re getting started, however, it’s sufficient to understand the value of links and engage in activities that have the potential to generate backlinks. After all, linking to other web pages is a fundamental part of what makes the web what it is.

The bigger concern is the inverse—if you don’t engage in any activity that could drive backlinks, you’re giving yourself a very slim chance of improving your search rankings.

Link building is a process that requires some trial and error.

Link generation ideas

Essentially, backlink generation happens in one of 2 ways.

1. Someone found your content and decided to link to you.
2. You put your content in front of someone and they choose to link to you.

Either way, you need to reach people with your content. There are many different approaches you can take to do so. What ends up being the most effective will depend on the type of content on your website, the type of people and businesses that might link to you, and how you might get them to look at your site.

• Suppliers and retailers. If you already have an existing business relationship with other establishments, encourage them to mention you on their website. Perhaps they already have a listings section—make sure your site is included on it.
• Partnerships. Mutually beneficial business partnerships have plenty of upsides already, but there’s no reason you can’t use an existing relationship to put the spotlight more firmly on your business. You could offer your partner some feature content to include on their website, or do some co-promotional activities like a webinar. This has the added benefit of exposing you openly to their audience.
• Local community. Supporting your local community is a great way to give something back while also spinning a positive story about your business. If you’re not already plugged into the local community, find out how you can get involved. This could include sponsoring events, running local meetups, or volunteering at local schools or universities.
• Testimonials. If you’re a happy user of products and services online, they might publish a case study or testimonial if you can provide a compelling success story. If you’re able to find the right person to ask, it’s a pretty easy sell. This content is super-useful for marketers looking to sell their products, and if you get a link out of it, it’s a win-win.
• Charities. Charity work can generate a lot of goodwill, and charities are often happy to spotlight companies that support them. While helping charities purely for link-building purposes is morally questionable, there’s no reason you can’t try to maximize the return on charity work you or your employees already do.
• Niche bloggers. In many industries, there exist passionate bloggers who constantly produce content for their own audience. Fostering relationships with these bloggers is an excellent way to give yourself a step up online. They already have an engaged audience who likes their content, and if your product or service is a good fit for their audience, there could be a range of benefits to collaboration. Offer to write a feature, send them samples, do an interview, or pay them to write on your site as a guest author.
• Press. While it can be difficult to get press, it offers potential because journalists are always looking for stories. If you happen to have a compelling story about your business or your products, it might intrigue them to hear it. The press also has the potential to multiply the reach of your story, as other news outlets pick up and republish stories to their audience.

With all these ideas, you should never pitch someone asking them to link to you. The link is a natural byproduct of the mention or feature. The idea is that you partake in activities where backlinks are a potential outcome. The best ideas are ones that offer business value even when you don’t get the backlink.

The importance of link building

The cornerstones of SEO are keyword research, on-page optimization, and acquiring backlinks. Doing one without the others will hamper your results. But among these, acquiring backlinks is probably the most important. Links are not just good for SEO. They can also be good for creating awareness and driving traffic. Link building should be a major part of your SEO strategy.