What Is SEO – Search Engine Optimization?

Search Engine Land

SEO stands for “search engine optimization.” In simple terms, SEO means the process of improving your website to increase its visibility in Google, Microsoft Bing, and other search engines whenever people search for:

Products you sell.
Services you provide.
Information on topics in which you have deep expertise and/or experience.

The better visibility your pages have in search results, the more likely you are to be found and clicked on. Ultimately, the goal of search engine optimization is to help attract website visitors who will become customers, clients or an audience that keeps coming back.

What you’ll learn in this guide:

How SEO differs from SEM and PPC
Why SEO is important
SEO types and specializations
How SEO works
How to learn SEO

How is SEO different from SEM and PPC?

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

Read on to learn more about both of these terms and how they’re related to SEO.

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 activities meant to drive traffic via organic search and paid search.

Put simply, search marketing is the process of gaining traffic and visibility from search engines through both paid and unpaid efforts.

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

SEO = driving organic traffic from search engines.
SEM = driving organic and paid traffic from search engines.

Now, this is where things get a bit confusing.

Today, many people use SEM interchangeably with PPC (which we’ll talk about in the next section).

This idea seems to undercut SEO. However, SEO is marketing, just like PPC is marketing.

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

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.

Basically, 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 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 – SEO is the unpaid side, PPC is the paid side.

Another key point: it’s important never to think of it as “SEO vs. PPC” (i.e., which one is better) because these are complementary channels. It’s not an either-or question – 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 into these articles:

How Wikipedia Turned PPC / Paid Search Into SEM
Does SEM = SEO + CPC Still Add Up?

Why is SEO important?

SEO is a critical marketing channel. First, and foremost: organic search delivers 53% of all website traffic.

That’s one big reason why 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.

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

But today, search is incredibly fragmented. 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, 61% of U.S. online shoppers start their product search on Amazon, compared to 49% who start on a search engine like Google. Also of note from that same research:

32% start on Walmart.com.
20% start on YouTube.
19% start on Facebook.
15% start on Instagram.
11% start on TikTok.

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:

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.

SEO 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.

Types of SEO

There are three types of SEO:

Technical SEO: Optimizing the technical aspects of a website.
On-site SEO: Optimizing the content on a website for users and search engines.
Off-site SEO: Creating brand assets (e.g., people, marks, values, vision, slogans, catchphrases, colors) and doing things that will ultimately enhance brand awareness and recognition (i.e., demonstrating and growing its expertise, authority and trustworthiness) and demand generation.

You maintain 100% control over content and technical optimizations. That’s not always true with off-site (you can’t control links from other sites or if platforms you rely on end up shutting down or making a major change), but those activities are still a key part of this SEO trinity of success.

Imagine SEO as a sports team. You need both a strong offense and defense to win – and you need fans (a.k.a., an audience). Think of technical optimization as your defense, content optimization as your offense, and off-site optimization as ways to attract, engage and retain a loyal fanbase.

Technical optimization

Optimizing the technical elements of a website is crucial and fundamental for SEO success.

It all starts with architecture – creating a website that can be crawled and indexed by search engines. As Gary Illyes, Google’s trends analyst, once put it in a Reddit AMA: “MAKE THAT DAMN SITE CRAWLABLE.”

You want to make it easy for search engines to discover and access all of the content on your pages (i.e., text, images, videos). What technical elements matter here: URL structure, navigation, internal linking, and more.

Experience is also a critical element of technical optimization. Search engines stress the importance of pages that load quickly and provide a good user experience. Elements such as Core Web Vitals, mobile-friendliness and usability, HTTPS, and avoiding intrusive interstitials all matter in technical SEO.

Another area of technical optimization is structured data (a.k.a., schema). Adding this code to your website can help search engines better understand your content and enhance your appearance in the search results.

Plus, web hosting services, CMS (content management system) and site security all play a role in SEO.

Content optimization

In SEO, your content needs to be optimized for two primary audiences: people and search engines. What this means is that you optimize the content your audience will see (what’s actually on the page) as well as what search engines will see (the code).

The goal, always, is to publish helpful, high-quality content. You can do this through a combination of understanding your audience’s wants and needs, data and guidance provided by Google.

When optimizing content for people, you should make sure it:

Covers relevant topics with which you have experience or expertise.
Includes keywords people would use to find the content.
Is unique or original.
Is well-written and free of grammatical and spelling errors.
Is up to date, containing accurate information.
Includes multimedia (e.g., images, videos).
Is better than your SERP competitors.
Is readable – structured to make it easy for people to understand the information you’re sharing (think: subheadings, paragraph length, use bolding/italics, ordered/unordered lists, reading level, etc.).

For search engines, some key content elements to optimize for are:

Title tags
Meta description
Header tags (H1-H6)
Image alt text
Open graph and Twitter Cards metadata

Off-site optimization

There are several activities that may not be “SEO” in the strictest sense, but nonetheless can align with and help contribute indirectly to SEO success.

Link building (the process of acquiring links to a website) is the activity most associated with off-site SEO. There can be great benefits (e.g., rankings, traffic) from getting a diverse number of links pointing at your website from relevant, authoritative, trusted websites. Link quality beats link quantity – and a large quantity of quality links is the goal.

And how do you get those links? There are a variety of website promotion methods that synergize with SEO efforts. These include:

Brand building and brand marketing: Techniques designed to boost recognition and reputation.
PR: Public relations techniques designed to earn editorially-given links.
Content marketing: Some popular forms include creating videos, ebooks, research studies, podcasts (or being a guest on other podcasts) and guest posting (or guest blogging).
Social media marketing and optimization: Claim your brand’s handle on any and all relevant platforms, optimize it fully and share relevant content.
Listing management: Claiming, verifying and optimizing the information on any platforms where information about your company or website may be listed and found by searchers (e.g., directories, review sites, wikis).
Ratings and reviews: Getting them, monitoring them and responding to them.

Generally, when talking about off-site, you’re talking about activities that are not going to directly impact your ability to rank from a purely technical standpoint.

However, again, everything your brand does matters. You want your brand to be found anywhere people may search for you. As such, some people have tried to rebrand “search engine optimization” to actually mean “search experience optimization” or “search everywhere optimization.”

SEO specialties

Search engine optimization also has a few subgenres. Each of these specialty areas is different from “regular SEO” in its own way, generally requiring additional tactics and presenting different challenges.

Five such SEO specialties include:

Ecommerce SEO: Additional SEO elements include optimizing category pages, product pages, faceted navigation, internal linking structures, product images, product reviews, schema and more.
Enterprise SEO: This is SEO on a massive scale. Typically this means dealing with a website (or multiple websites/brands) with 1 million+ pages – or it may be based on the size of the organization (typically those making millions or billions in revenue per year). Doing enterprise also typically means delays trying to get SEO changes implemented by the dev team, as well as the involvement of multiple stakeholders.
International SEO: This is global SEO for international businesses – doing SEO for multiregional or multilingual websites – and optimizing for international search engines such as Baidu or Naver.
Local SEO: Here, the goal is to optimize websites for visibility in local organic search engine results by managing and obtaining reviews and business listings, among others.
News SEO: With news, speed is of utmost importance – specifically making sure you get into Google’s index as quickly as possible and appear in places such as Google Discover, Google’s Top Stories and Google News. There’s a need to understand best practices for paywalls, section pages, news-specific structured data, and more.

How does SEO work?

If you found this page via Google search, you likely searched Google for [what is seo] or [seo].

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

Originally published in 2010, our “what is SEO” page has earned a whopping 324,203 links.

Put simply, these factors (and others) have helped this guide earn a good reputation with search engines, which has helped it rank in Position 1 for 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.