(SEO) Search engine optimiation

Get started learning the basics of search engine optimization – how SEO works, why it’s important, the different types of SEO and much more.

SEO stands for Search Engine Optimization and helps search engines understand your website’s content and connect it with users by delivering relevant, valuable results based on their search queries.

The goal of SEO is to rank on the first page of search engine results pages (SERPs) for the most relevant and valuable keywords to your target demographic, driving qualified traffic to your site.

SEO is considered a digital marketing practice and can be applied to any website. It helps improve a site’s visibility on search engines like Google and Microsoft Bing. Whether your site promotes products, offers services, or shares expert knowledge on a specific topic, SEO can help drive traffic and increase online visibility.

The better visibility your pages have in search results, the more likely you are to be found and visited.

This introductory guide will explain in more detail what SEO is and what it entails in 2025.

Technology is constantly evolving, which means that websites – and the way they are structured – evolve. So do the devices we use to access search engines.

A web search can be voice activated and a click may be a tap on a mobile phone screen. Even the results we see from our search engine of choice may be summarized by artificial intelligence (AI).

We will explain all these different aspects of SEO as well as provide resources for your continued learning.

How is SEO different from SEM and PPC?

SEM and PPC are two other common terms you will read about often here on Search Engine Land and hear about in the larger search marketing community.

It can also be helpful to distinguish what SEO is from what it is not.

Here, we’ll explain the difference in terminologies, what these abbreviations mean and how they extend to different disciplines.

SEO vs. SEM

SEM stands for search engine marketing – or, as it is more commonly known, search marketing.

Search marketing is a type of digital marketing. It is an umbrella term for the combination of SEO and PPC (pay-per-click, e.g. Google Ads) activities that drive traffic via organic search and paid search, respectively.

So how do SEO and SEM differ? Technically they aren’t different – SEO is simply one-half of SEM:

• SEO: Driving organic results clicks from search engines.
• SEM: Driving organic and paid results clicks from search engines.
• PPC: Driving paid results clicks from search engines.

Here’s the best way to think about SEM, SEO and PPC:

Imagine SEM is a coin. SEO is one side of that coin. PPC is on the flip side.

SEO vs. PPC

PPC: stands for pay-per-click – a type of digital marketing where advertisers are charged whenever one of their ads gets clicked on.

Advertisers bid on specific keywords or phrases that they want their ads to appear for in the search engine results.

When a user searches for one of those keywords or phrases, the advertiser’s ad (paid listing) will appear among the top results.

So again, if we think of search marketing as a coin, SEO and PPC are two sides of the same coin:

• With PPC, the advertiser pays when a search user clicks their paid listing.
• With SEO the search result listing has not been directly paid for, though SEO is sold as a service and the process of optimizing pages and websites takes time and investment, so it is important to understand that organic search isn’t “free.”

Some people have debated “SEO vs. PPC” – which channel is more valuable or has a better return on investment (ROI). However, SEO and PPC are complementary digital marketing channels. Ideally, you should always choose both (as long as your budget allows it).

As we mentioned before, the terms SEM and PPC are used within the industry interchangeably. However, that isn’t the case here on Search Engine Land.

Whenever we mention “SEM,” it will be because we’re referring to both SEO (organic search) and PPC (paid search).

If you’re curious about the history behind how “SEM” came to mean “PPC” at the exclusion of SEO, you can dig deeper in these articles:

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Why is SEO important?

SEO is a critical marketing channel.

• Organic search delivers 53% of all website traffic, according to a 2019 BrightEdge study.
• More than 8.5 billion searches happen every day on Google Search and Google owns 91% of the global search engine market.

With such incredible audience reach, there’s no surprise that in turn, the global SEO industry is forecast to reach a staggering $122.11 billion by 2028.

SEO drives real business results for brands, businesses and organizations of all sizes. This is because the act of searching, or the search user interface (be it a typed, voiced or image query format) has become second nature for internet users worldwide, as the primary way to access the information sought, within the sea of billions of webpages (4.3 billion pages on the indexed web, as of September 2024).

Whenever people want to go somewhere, do something, find information, research or buy a product/service – their journey typically begins with a search.

However, search is incredibly fragmented – particularly for consumer-intent activities. Users may search on traditional web search engines (e.g., Google, Microsoft Bing), social platforms (e.g., YouTube, TikTok) or retailer websites (e.g., Amazon).

In fact, last year 56% of U.S. online shoppers started their product search on Amazon, compared to 46% who started on a search engine like Google. Also of note from that same research: 

Another interesting aspect of this data compared to the previous years is the growth in social sources, particularly TikTok, as a place to search for both products and knowledge searches (think “how to do X” types of search activities). 

In fact, when it comes to Gen Z a staggering 51% of women in this age group prefer to start a search on TikTok above all other online sources of information according to a 2023 study.

Trillions of searches are conducted every year. Search is often the primary source of traffic for websites, which makes it essential to be “search engine friendly” on any platform where people can search for your brand or business. 

What this all means is that improving your visibility, and ranking higher in search results than your competition, can positively impact your bottom line,

SEO is also incredibly important because the search engine results pages (or SERPs) are super competitive – filled with search features (and PPC ads). SERP features include:

• AI Overviews.
• Knowledge panels.
• Featured snippets.
• Maps.
• Images. 
• Videos.
• Top stories (news).
• People Also Ask.
• Carousels.

Another reason SEO is critical for brands and businesses: unlike other marketing channels, good SEO work is sustainable. When a paid campaign ends, so does the traffic. Traffic from social media traffic is at best unreliable – and a fraction of what it once was.

SEO is the foundation of holistic marketing, where everything your company does matters. Once you understand what your users want, you can then implement that knowledge across your:

• Campaigns (paid and organic).
• Website content.
• Social media properties.

Organic search is a channel that drives the traffic you need to achieve key business goals (e.g., conversions, visits, sales). It also builds trust – a website that ranks well is generally regarded as authoritative or trustworthy, which are key elements Google wants to reward with better rankings.

How does SEO work?

If you found this page via Google, you likely searched for something along the lines of [what is seo?]

This guide is published on Search Engine Land, an authoritative website with expertise and experience in SEO topics (we’ve been covering all SEO changes, big and small, since 2006). 

Originally published in 2010, this What is SEO page has earned hundreds of thousands of links.

Put simply, these factors (and others) have helped this guide earn a good reputation with search engines, which has helped it rank in a top 1-3 organic search position in most search engines, for a number of years. It has accumulated signals that demonstrate it is authoritative and trustworthy – and therefore deserves to rank when someone searches for SEO. 

But let’s look at SEO more broadly. As a whole, SEO really works through a combination of:

• People: The person or team responsible for doing or ensuring that the strategic, tactical and operational SEO work is completed.
• Processes: The actions taken to make the work more efficient.
• Technology: The platforms and tools used.
• Activities: The end product, or output.

Many other things factor into how SEO works. What follows is a high-level look at the most important knowledge and process elements. 

Six critical areas, in combination, make SEO work:

1. Understanding how search engines work

If you want people to find your business via search – on any platform – you need to understand the technical processes behind how the engine works – and then make sure you are providing all the right “signals” to influence that visibility. 

When talking about traditional web search engines like Google, there are four separate stages of search:

• Crawling: Search engines use crawlers to discover pages on the web by following links and using sitemaps.
• Rendering: Search engines generate how the page will look using HTML, JavaScript and CSS information.
• Indexing: Search engines analyze the content and metadata of the pages they have discovered and add them to a database (though there’s no guarantee that every page on your website will be indexed).
• Ranking: Complex algorithms look at a variety of signals to determine whether a page is relevant and of high enough quality to show when searchers enter a search query.

However, optimizing for Google search is different from optimizing for search other platforms like YouTube or Amazon.

Let’s take Facebook, for example, where factors such as engagement (Likes, comments, shares, etc.) and who people are connected to matter. Then, on Twitter, signals like recency, interactions, or the author’s credibility are important. 

And further complicating things: search engines have added machine learning elements in order to surface content – making it even harder to say “this” or “that” resulted in better or worse performance.

2. Researching

Research is a key part of SEO. Some forms of research that will improve SEO performance include:

• Audience research: It’s important to understand your target audience or market. Who are they (i.e., their demographics and psychographics)? What are their pain points? What questions do they have that you can answer? 
• Keyword research: This process helps you identify and incorporate relevant and valuable search terms people use into your pages – and understand how much demand and competition there is to rank for these keywords.
• Competitor research: What are your competitors doing? What are their strengths and weaknesses? What types of content are they publishing? 
• Brand/business/client research: What are their goals – and how can SEO help them achieve those goals?
• Website research: A variety of SEO audits can uncover opportunities and issues on a website that are preventing success in organic search. Some audits to consider: technical SEO, content, link profile and E-E-A-T. 
• SERP analysis: This will help you understand the search intent for a given query (e.g., is it commercial, transactional, informational or navigational) and create content that is more likely to earn rankings or visibility.

3. Planning

An SEO strategy is your long-term action plan. You need to set goals – and a plan for how you will reach them. Think of your SEO strategy as a roadmap. The path you take likely will change and evolve over time – but the destination should remain clear and unchanged.

Your SEO plan may include things such as:

• Setting goals (e.g., OKRs, SMART) 
• Setting expectations (i.e., timelines/milestones).
• Defining and aligning meaningful KPIs and metrics.
• Deciding how projects will be created and implemented (internal, external or a mix).
• Coordinating and communicating with key stakeholders.
• Choosing and implementing tools/technology.
• Hiring, training and structuring a team.
• Setting a budget.
• Measuring and reporting on results.
• Documenting the strategy and process.

4. Creating and implementing

Once all the research is done, it’s time to turn ideas into action. That means:

• Creating new content: Advise your content team on what content needs to be created.
• Recommending or implementing changes or enhancements to existing pages: This could include updating and improving the content, adding internal links, incorporating keywords/topics/entities, or identifying other ways to optimize it further.
• Removing old, outdated or low-quality content: This is any content that isn’t ranking well, driving converting traffic or helping you achieve your SEO goals.

5. Monitoring and maintaining

You need to know when something goes wrong or breaks on your website. Monitoring is critical. 

You need to know if traffic drops to a critical page, pages become slow, unresponsive, or fall out of the index, your entire website goes offline, links break, or any other potential catastrophic issues.

6. Analyzing, assessing and reporting on performance

If you don’t measure SEO, you can’t improve it. To make data-driven decisions about SEO, you’ll need to use:

• Website analytics: Set up and use tools (at minimum, free tools such as Google Analytics, Google Search Console and Bing Webmaster Tools) to collect performance data.
• Tools and platforms: There are many “all-in-one” platforms (or suites) that offer multiple tools, but you can also choose to use only select SEO tools to track performance on specific tasks. Or, if you have the resources and none of the tools on the market do exactly what you want, you can make your own tools.