Editor’s note: This is a chapter from Search Engine Journal’s new e-book, SEO 101: Learn the Basics of Search Engine Optimization. Want to read the full guide? Download your copy of SEO 101 now!

In the early days of SEO, web ranking was heavily based on keyword usage within the page’s content.

Without sophisticated search engine algorithms, keyword usage was the easiest way to rank pages.


The logic was simple: the more a keyword phrase was used on a webpage, the more likely that was what the page was really about.

Unfortunately, SEO practitioners of the time took advantage of this system and used keywords unnaturally by overusing the targeted keyword phrase in order to rank higher.

This method is known nowadays as keyword stuffing.

This causes sites to rank for keyword phrases even when the site doesn’t have much to offer on a topic.

A new way to look and evaluate sites on what ranks and what doesn’t was needed and should go beyond analyzing content alone.

Along Came Google: The Emergence of Google & PageRank

Google started in 1996 through a partnership between its founders, Larry Page and Sergey Brin.

The search engine’s early ranking algorithm was based on the PageRank algorithm, developed by and named after Page while he was studying information retrieval at Stanford University.

The main idea was to use links between webpages as a ranking factor.

Google’s archived About page states that:

PageRank works by counting the number and quality of links to a page to determine a rough estimate of how important the website is. The underlying assumption is that more important websites are likely to receive more links from other websites.

Feel free to read all about the PageRank algorithm. This is all public information and the PageRank patent is viewable for free online.

It is a very technical document and readers may need more advanced programming and mathematical knowledge to comprehend it in its entirety.

Instead of reading through all of the details behind how Google analyzes and evaluates links, it may be more worthwhile to understand why this algorithm even looks at links in the first place.

Internal, Inbound, & Outbound Types of Links

A link or hyperlink is a clickable object on a webpage that leads from one page to another. Links may visibly appear as text, images, or buttons.

We can classify links based on the destination of the link, whether it leads users to another page on the same site or a different website.

Internal links are links between the pages within your own website.

Search engines determine this by looking at the domain name; if the links on a page link to other pages within the same domain, they are considered internal links.

If, for some reason, your website was built to have more than one domain, search engines will view this as an external link.

Inbound links are links that come from other websites or a different domain name.

Outbound links are those links on your website that link out to websites with a different domain name.

Inbound Link Focus: Natural Links from High-Quality Pages for Greater SEO Benefits

Out of the three types of links, inbound links are the ones with the greatest SEO benefit, but they are also the hardest to obtain.

High-Quality Pages Are like Friends You Go to for Advice: They’re Trustworthy, Credible, & Have Some Sort of Authority on the Topic.

Whenever any webpage links to another webpage, the creator of the content that used the link did it for a reason.

Often, they like the page they are linking to because it has information that supports or builds on the information on the first page.

On the other hand, some authors link to pages for the opposite reason; they may be linking to a page they want to criticize or don’t agree with.

However, both of these links are good for the page being linked to. Whether the content is loved or despised, it has provoked a strong reaction, which indicates quality content.

If the content of a page makes someone talk, it indicates authority, credibility and/or trustworthiness.

Thus, links on pages are like votes of trust, credibility, and authority.

The more links a page gets, the more votes they are getting, which can improve their ranking.

However, the quantity of links that a page gets is not all that matters.

Google also evaluates the quality of the links.

Nobody Likes Fake Friends

Sometimes you identify fake people right away. Other times, it isn’t so easy.

The same is true when Google looks at webpages. Links that seem like votes of trust can easily be faked using things like:

These are called artificial links.

Sometimes, Google identifies that the links are fake right away, but not always. It can take Google a while to identify artificial links.

These artificial links have negative consequences for the pages.

The rank of these pages with artificial links can be hurt by various ranking factors monitoring link quality, as well as algorithm updates, or even manual actions from Google.

In order to have good, natural links, a site needs quality content that is trustworthy, credible, and authoritative.

This allows the pages to gain quality, natural links from other websites, which will help their ranking.

Inbound Links Are Still Important Even After Google’s Penguin Update

In recent years, Google has implemented a series of important algorithm updates. One of these important updates was Penguin.

Google’s Penguin update has now become an essential part of the core algorithm.


The Penguin update allows Google to evaluate the quality of links more effectively.

After this update, some SEO professionals were under the impression that links no longer mattered; however, this is not the case.

Links are important in ranking and still indicate the same values as before.

Links serve as a reflection of the quality of a page’s content as long as they are natural links.

The Penguin update made it easier for Google to identify artificial links.

Links have always been important ranking factors; however, the methods of obtaining links has evolved, especially after the Penguin update arrived.

Everyone Doesn’t Think Like an SEO, Don’t Over Do Anchor Text

One of the important aspects of inbound links that search engines pay attention to is the anchor text of a link.

Anchor text is the clickable text of a link or the alternative text of an image in image links.

The anchor text helps give search engines an idea of the topic of the destination page.

Historically, this was abused and made link bombing possible, which is simply using the exact phrase you want to rank for in all the inbound links’ anchor text from thousands of webpages, regardless of the quality or relevancy of the page.

Many previous Google updates addressed this issue, including the Penguin update, where overdoing keyword-focused anchor text can appear unnatural and may negatively affect ranking.

Ever since the Penguin update, there has been a strong focus on having natural anchor text in your inbound links.

Here are a couple things to look out for that may jeopardize your link building efforts:

Internal Link Focus: Distribute PageRank Well Across Your Site

Inbound links are the most beneficial because PageRank gets passed on from other sites to your site.

The more inbound links you get, the more PageRank you receive.

As a chain of links hop from one page to another, the flow of PageRank gets weaker and weaker.

In almost any website, the page with the most inbound links is the homepage of the site. Therefore, if a page within your site is too far from the homepage, the PageRank will decrease significantly before reaching the page.

This causes pages that are linked really far from the home page to rank poorly. Since not all pages will get inbound links, your internal links should serve two purposes:

Here are the common areas where you will find internal links:

Even if we’re emphasizing to use internal links in the distribution of PageRank, always make sure the users are the highest priority. Always design sites, and think of internal links for users first, then search engines second, and learn all best practices on internal site navigation.

Outbound Link Focus: Just Appear Natural

Over the years, SEO pros have evolved how they use outbound links.

Some believed that outbound links took away PageRank, decreasing its potential to rank.

For some number of years, this may have been correct.

This is where terms like “PageRank hoarding” and “PageRank channeling” came from.

Any outbound link was the equivalent of a leak. But if an outbound link was necessary for users, you could add the nofollow link attribute.

The nofollow was like telling search engines, “don’t follow this link and give my PageRank to that page.”

However many SEO practitioners abused this until Google came up with an update in 2009 on PageRank evaporation.

In a nutshell, PageRank hoarding just didn’t work like it used to. Multiple theories and best practices have sprung out of this, such as:

In all these three bullet points, the rules may appear conflicting.

No outbound links preserve PageRank, but no links at all look fishy.

Adding a nofollow should help preserve PageRank, however, if links are all nofollow, they look more unnatural.

Conventional wisdom taught us that outbound links leak out PageRank and that is still true today, but it is recommended to link to good quality sites.

The rules here don’t seem to be set in stone and is somewhat flexible, but the main rule that is valid and applies to all rules above is to appear natural.

Link out to other sites if it is the natural thing to do.


Links have been an important part of SEO. They still are. And it looks like it will still be important in the years to come.

However, like many other things in SEO, how optimization was done in the past is much different compared to how it is done today.

We classify links as inbound links, outbound links, and internal links.

If there is one single theme across all these types of links, it will mainly be link naturally. If it looks bad to humans, most probably it looks bad to search engines.

More Link Building Resources:

Featured Image Credit: Paulo Bobita