What is SEO (Search Engine Optimization)?

What is SEO (Search Engine Optimization)?

Do you have a website or are you thinking about creating one? And do you want to attract more people to your business? If the answer is yes, then there’s no doubt about it: SEO should be part of your marketing efforts. It’s a great way to build your brand and get people on your site. But what does it actually entail? In this post, we’ll give you an understanding of what SEO is and how you can get started!

What is SEO?

The acronym SEO stands for Search Engine Optimization. Let’s first get a definition from one of our principal SEO experts at Yoast, Alex Moss:


SEO is both the art and science of improving a website, and pages within, to be as visible as possible for when people search for a relevant topic within any search platform. SEO covers many areas from technical aspects including optimizing a site’s performance and structure, to enhancing brand authority by providing great content and matching it with that person’s search intent.

Alex Moss – Principal SEO at Yoast


So how does Google work? With search engines like Google, the process consists of crawling, indexing, and ranking. The crawler is an online bot that scours the web to collect all the pages out there and save them in a gigantic database called the index. This index is constantly updated with new pages or updated versions of existing ones. When someone searches online, the search engine calls on the index and uses complex algorithms to determine which pages are relevant to show. This determines the ranking of results shown to the online searcher.

For example, when I search for the term ‘sustainable phone case’, these results are shown by Google. Based on my search term and the intent behind it, Google deems these results the best ones found in its index.

search results for search query sustainable phone case
Screenshot of Google’s results for ‘sustainable phone case’

Organic vs paid search

SEO is focused on attracting more organic traffic to your website, traffic that comes to your site via unpaid search results. But as you can see in the image above, the search results also show ads and sponsored results. Often at the top of the page. To make a clear distinction, there are a few acronyms in use that are valuable to know:

  • SEM: Search engine marketing entails all marketing efforts to show up in the search results, both through ads and organic results.
  • SEO: SEO is the practice of improving a website to show up when people search for a relevant topic within any search platform. 
  • SEA: Search engine advertising is the practice of paying for ads that show up in the search results of relevant keywords.
  • PPC: Pay-per-click. The advertising model used in SEA, where the advertiser pays a fee each time one of their ads is clicked.

These paid results can allow you to show up as the top result for a search term, but it will cost you money every time a user clicks through to your website. When comparing SEO vs PPC, they both have their benefits and drawbacks. But more often than not, they complement each other well.

Why SEO is important for site owners

Huge volume of searches

The reason that so many (big) companies heavily invest in SEO is the high impact that it can have when done right. To give you an idea, Google, the most-used search engine got around 8.3 billion searches per day in 2024. A number that has only gone up (and significantly) since 1998. So if you have a website, you want to make sure to show up in Google and other search platforms.

SEO is intent-driven

Online search is very intent-driven. Unlike other marketing channels, such as social media, where people happen to scroll upon your brand and content. This means you’re interrupting a user’s experience to capture their attention, which makes it more difficult to get them interested. Showing up in their search results aligns with an existing demand—your customers are actively seeking information, products, or solutions. This makes SEO a powerful inbound marketing strategy, where users come to you rather than the other way around. Because searchers already have intent, they are more likely to convert, making SEO an essential tool for attracting high-quality leads.

Competitive advantage

Creating a website and leaving it at that isn’t going to cut it. With new websites popping up left and right, it’s becoming increasingly difficult to get noticed and maintain customer loyalty. SEO can provide you with higher online visibility, a stronger brand, more authority in your field, more contact moments with your audience and higher quality traffic to your website (and/or offline location). All of this, leading to higher brand loyalty and more revenue.

Types of SEO

Although the basic principles remain the same, there are a few different types of SEO worth mentioning. They may not all apply to your situation, but it is beneficial to dive into the ones that do:

  • Ecommerce SEO: SEO specifically focused on gaining more visibility and organic traffic for online stores. With the goal of acquiring more sales.
  • Local SEO: Local SEO is the practice of optimizing your website for a specific local area. This is to ensure you are easily found (both online and offline) by a local audience. 
  • Video SEO: The process of optimizing videos and video pages to make them appear in the search results for relevant keyphrases. Whether that is Google’s search results or search results on other platforms like YouTube and social media.
  • News SEO: Mainly relevant for news publishers, news SEO focuses on getting content to show up as the top result in Google News and other news-specific areas of the search results.

The 3 pillars of SEO

SEO is all about optimizing your website to increase your online visibility. But what do we mean by that? What exactly should you be optimizing? Well, there’s a lot you can do and it can be divided up into three main areas.

Illustration of the 3 pillars of SEO
The 3 pillars of SEO: Technical SEO, on-page SEO, and off-page SEO.

Technical SEO

First of all, it’s important to focus on the technical part of SEO. Technical SEO is all about improving a website’s technical aspects to improve user experience and make search engines understand your pages. Aspects that fall under technical SEO are:

  • Loading time of your pages
  • Making the right parts of your site crawlable for search engines
  • The amount of dead links on your site
  • Security 
  • Use of structured data

Search engines value these aspects because they want to present their users with websites that provide a proper user experience. A page that takes forever to load, doesn’t exist anymore, or isn’t secure, provides a terrible user experience and will not make users happy. Also, aspects such as crawlability and structured data help search engines understand what your pages are about. This helps search engines understand your relevance and allows them to rank your pages higher.

On-page SEO

Although technical SEO is also part of on-page SEO, this can be seen as ‘under-the-hood’ optimization to improve your pages. The other efforts that can be categorized as on-page SEO are targeted at optimizing the content on a page. Think of:

  • The quality of your content
  • Use of the proper keywords
  • Showing E-E-A-T in your content
  • Site structure
  • Internal linking
  • Well-thought-out URLs, titles, and alt tags 

On-page SEO mainly revolves around content SEO and using the elements around that content to improve your findability for relevant terms. 

Off-page SEO

In contrast to on-page SEO, off-page SEO entails everything you do for SEO outside of page optimization. Such as external link building, social media and local SEO (off-site). This is focused on growing your reach and building your brand to attract more traffic. An important part is link building, getting other relevant websites to link to your content. This can really help boost your visibility and improve your reputation as an authority – see links as like votes of confidence from other websites 

But there’s a lot more you can do. For example, speaking at events, doing interviews, and blogging for other websites. These activities give you the opportunity to showcase your expertise and reach new people. When you own a local shop, these might not be as relevant. In that case, it’s important that you focus on the experience that people have with your shop. Make sure that customers leave happy and that this experience is positive, offline and online. This also extends to social media. Although your activity there does not directly impact rankings, it pays off to be in contact with your audience there as well. And provide a similar (positive) experience through these platforms as well. 

One final aspect that you shouldn’t forget about is your business listings. Make sure these are accurate on your Google Business Profile and other websites that are relevant to your business.

SEO Ranking factors

To determine what results to show, and in what order, search engines use ranking factors. Ranking factors, or ranking signals, are characteristics of a page that search engines look at to determine how relevant that page is for a specific search query. Although the exact list of ranking factors and their importance is a bit of a mystery and changes from time to time, we do have a pretty good idea of the most important ones:

  • The quality, relevance and usability of your content
  • External and internal links
  • The technical aspects of your site (f.e. security)
  • User experience on your site (site speed, easy navigation, mobile parity)
  • The overall online presence of your brand

In addition to these top-ranking factors, there are plenty of others (both known and unknown). But to get a head start with SEO, it makes sense to focus on these aspects first.

SEO now vs early days: a brief history

SEO in the 90’s

Although websites have been around for a little while longer, people started optimizing their sites for search engines in the mid-1990s. As you can imagine, SEO was a lot simpler back then. The algorithms that search engines used were way less advanced and relied on ranking factors like keyword density to determine the relevance of a page. The ‘trick’ back then was making sure the keyword was being used enough times throughout your page and in your meta tags. 

Search engines evolving

Naturally, the companies behind search engines quickly realized the issue with this approach. Displaying the results that use the keyword most isn’t always the best experience for their users. So they had to find a way to better handle how potential results were being ranked. Search engines like Google started working on ways to get smarter and rely less on ‘tricks’ and static ranking factors. This resulted in a number of algorithm updates, each resulting in a smarter Google that was more capable of understanding the relevance of a page. 

With a team working non-stop on improving Google’s search engine, the focus moved from factors like keyword density to user experience and high-quality content. These algorithm updates are still very much a part of the SEO field, with Google releasing a new one (or multiple) every year. You can expect this to be a continuous process where search engines adapt to current search behaviour and adjust their algorithms to keep showing users the best results for their search query. 

SEO in 2025

So, where does that leave us in 2025? As mentioned, search engines continue working on their algorithms to improve their users’ experience. The focus points of SEO in 2025 are still high-quality content and technical factors like site speed, security and mobile parity. But there are more aspects that Google and other search engines deem important.

Search engines are working hard to get a better understanding of a user’s search intent, to show that user the results that fit their need best. Related to that, they continue to improve how information is presented in the search results, which can differ quite a bit per search intent. 

AI overview for search term site structure
A possible zero-click search, where the definition of site structure is shown in an AI overview.

One result of that is zero-click searches, where search engines show the complete answer to a search query in the search results. This can lead to fewer clicks to your website, but it still pays off to be the website that provides that answer. In fact, this is a good example of the direction in which SEO is going. Shift your focus from ‘just clicks’ and maintaining a specific spot in the search results to building a strong brand and being visible on different platforms.   


In 2025, SEO will focus less on raw keywords and more so around search intent across diverse platforms like social media and LLMs. As well as this, it’ll be important to produce more video content as discovery platforms integrate these more into their SERPs.

Alex Moss – Principal SEO at Yoast


The other aspect we can’t ignore is AI. More people are using AI tools for their online searches and search engines are also investing in providing AI-driven search experiences. An example of that is Google AI overviews, where Google uses AI to pull together and combine information on a search query from different resources. This is then shown in one overview, with the hope that this directly answers the specific question asked. 

Setting SEO Goals

SEO experts used to closely monitor ranking positions, clicks, website traffic and stats like bounce rates. Naturally, all of this data is still relevant, but there has been a shift in what goals to focus on. Search behavior has changed, and search engines are showing your content in many different ways. So it’s not just a number game anymore. You need to focus on the overall perception of your brand and being present in the right places. 

Set SEO goals related to engagement, brand awareness, user experience on your website, user satisfaction, and how all of this can be related to sales or other actions you want your audience to perform. This can be trickier than just looking at your daily rankings but will give you a better idea of the success of your SEO strategy and how you’re perceived.  

How to learn SEO and get started

Although it consists of a lot of different aspects, it is possible to tackle (a lot of) SEO yourself. Let’s look at how you can do that and what resources can help you get started. 

Start with the basics

Before you get to content creation, it’s important to get your technical SEO in order. If you know your way around redirects, optimizing page speed, crawlability, security and structured data, make those your first priority. If not, let your site builder help you out or hire someone with a background in technical SEO. When that’s done, you can start looking at site structure and the content on your pages.

By doing keyword research, you will be able to create content that aligns with your business and gets people to your website. It will also give you loads of input on topics to write about. This will enable you to set up an SEO strategy and plan to continue working on this throughout the year. Because SEO is never done. That’s why it’s important to create a realistic plan and keep yourself (or your team) to it. This might feel like a lot of effort, but remember that SEO not only brings more traffic to your site, it also helps build your brand and increase user loyalty in the long run. 

How we can help you

At Yoast, we want to make SEO accessible for everyone. And we want to help you do it yourself. That’s why we offer a free and Premium version of our WordPress plugin, allowing you to get started with SEO without too much trouble. Our free plugin comes with features like the SEO and readability analyses, which give you feedback on your content right away. It also handles parts of the technical SEO for you. Our Premium plugin gives you access to some more features like AI-powered features, a redirect tool, and the possibility to add multiple keywords per page. Making SEO even easier to work on. 

We also offer a variety of SEO courses in our Yoast SEO academy, where you can find 5 free courses to get started. For example, the SEO for beginners course, the WordPress for beginners course and a course on structured data. If you’re a Yoast SEO Premium user, you get access to all 16 courses on there. Which will really help you dive into the different aspects of SEO and how to tackle them. 

Finally, we have an SEO blog with numerous blog posts on SEO basics, more advanced SEO, new developments and related topics. All of this to make sure that you have all the tools you need to successfully work on SEO yourself!

Read more: The ultimate guide to WordPress SEO »

The post What is SEO (Search Engine Optimization)? appeared first on Yoast.

Maggi Pier

Maggi Pier

Avid gardener, artist, writer, web designer, video creator, and Google my Business local marketing pro!

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