What Is SEO – Search Engine Optimization?

SEO, or Search Engine Optimisation, is the practice of improving your website’s visibility in search engine results pages (SERPs) by making it easier for search engines to understand and rank your content. The goal is to connect your website with users through relevant and valuable search results based on their queries.

The core objective of SEO is to achieve high rankings for targeted keywords, which attracts qualified traffic to your site. Whether your website offers products, services, or knowledge on specific topics, effective SEO can significantly boost your online presence, drive traffic, and help users find you.

Improved visibility in search results leads to more potential visitors, which ultimately enhances your website’s reach and success.

As technology constantly advances, so do websites and the ways we search for information. With the growing use of voice search and mobile browsing, search results are now also influenced by AI. This evolving landscape means SEO strategies must adapt.

In this guide, we’ll dive into the fundamentals of SEO, how it works, and the different aspects you should be aware of in 2025. We’ll also provide useful resources to continue your SEO learning journey.

SEO vs. SEM and PPC

When talking about search marketing, it's essential to distinguish between SEO, SEM, and PPC.

SEM (Search Engine Marketing) is an umbrella term that includes both SEO (organic search) and PPC (Pay-Per-Click advertising). While SEM encompasses both organic and paid search traffic, SEO focuses solely on organic results, while PPC involves paying for ad placements in search engines.

PPC works by advertisers bidding on keywords to display ads in search results. When users click on those ads, advertisers pay for the click. In contrast, SEO involves optimising a website to appear in unpaid, organic search results.

Both SEO and PPC are part of SEM, but they differ in how they drive traffic:

SEO: Organic, unpaid traffic driven by search engine rankings.
PPC: Paid traffic driven by ads.

Why SEO is Important

SEO is crucial for digital marketing, with organic search accounting for 53% of website traffic. Given the vast number of searches conducted daily, especially on platforms like Google, SEO remains a powerful tool for businesses to increase visibility and reach.

In fact, 91% of global searches are conducted on Google, and search engine marketing is projected to reach over $122 billion by 2028. SEO connects businesses with users actively seeking information, products, or services, making it one of the most effective ways to attract potential customers.

As search patterns shift to include voice search, social media, and e-commerce platforms, SEO continues to evolve. It's not just about ranking high on traditional search engines anymore—visibility on platforms like Amazon, YouTube, and even TikTok also matters.

Understanding SEO’s importance means recognising that a significant portion of users’ online journeys begins with a search query. By optimising your site for relevant keywords and queries, you can ensure that your content is found by the right audience, regardless of where they search.

Another notable shift in recent years is the rise of social media platforms, particularly TikTok, as major sources for product searches and informational queries, such as “how to do X.” This trend is especially evident among Gen Z. A 2023 study found that 51% of Gen Z women prefer to start their search on TikTok rather than any other platform.

With trillions of searches conducted annually, search engines remain a primary driver of traffic for websites. It’s crucial for businesses and brands to optimise their content for search, ensuring they’re “search engine friendly” on any platform where consumers may look for them.

Higher visibility and ranking better than competitors can significantly boost your business's bottom line. Given that search results pages (SERPs) are increasingly competitive—with features like AI Overviews, Knowledge Panels, Featured Snippets, Maps, Images, Videos, Top Stories, and People Also Ask—SEO plays a key role in securing valuable organic traffic.

Unlike other marketing channels, SEO offers long-term benefits. While paid campaigns generate traffic only during their duration, and social media traffic can be unreliable, effective SEO provides sustainable visibility over time, making it an essential strategy for any brand.

SEO as the Foundation of Holistic Marketing

SEO is the cornerstone of holistic marketing—everything your company does plays a role. By understanding what your users are looking for, you can implement that knowledge across every aspect of your marketing efforts, including:

Campaigns (both paid and organic)
Website content
Social media presence

Organic search is a key channel that drives the traffic necessary to meet your business goals, whether that’s increasing conversions, visits, or sales. It also helps build trust. A well-ranked website is often seen as more authoritative or trustworthy, two important qualities Google rewards with higher rankings.

Types of SEO and Specializations

Think of SEO like a sports team: to win, you need a strong offense, defense, and a loyal fanbase.

Technical SEO: This is your defense. It focuses on optimizing a website's technical elements to ensure it’s crawled and indexed correctly.
Content SEO: This is your offense. It involves optimizing website content to appeal to both users and search engines.
Off-site SEO: These are the strategies that help you build a loyal following, raise brand awareness, and demonstrate authority and trust.

You have complete control over content and technical optimizations, but off-site SEO involves external factors, such as earning links from other sites and relying on platforms that could change.

Technical SEO: Optimizing Website Elements

A solid technical foundation is essential for SEO success.

Website Architecture: Ensure your website is easily crawled and indexed by search engines. As Gary Illyes, Google’s trends analyst, advised: "MAKE THAT DAMN SITE CRAWLABLE."
Key Technical Elements: URL structure, internal linking, and navigation are vital.
User Experience: Search engines prioritize pages with fast loading speeds, mobile-friendliness, and a positive user experience (e.g., Core Web Vitals, HTTPS).
Structured Data (Schema): Use structured data to help search engines understand your content better and enhance your visibility in search results.
Hosting, CMS, and Security: All play important roles in SEO.

Content Optimization: Making Your Content Work for Both People and Search Engines

SEO content must be optimized for both humans and search engines.

For Users: Content should cover relevant topics, include helpful multimedia, be well-written, and be easy to understand (using subheadings, bullet points, etc.).
For Search Engines: Key elements include optimizing title tags, meta descriptions, header tags (H1-H6), image alt text, and Open Graph metadata.

Generative Engine Optimization (GEO) is an emerging field that focuses on optimizing content for AI-driven search engines like Google’s AI Overviews and OpenAI’s ChatGPT.

Brand and Authority Building (Off-site SEO)

Off-site SEO refers to activities outside your website that indirectly affect your SEO.

Link Building: Acquiring high-quality links from authoritative sites remains crucial. Quality matters more than quantity.
Website Promotion Methods:
- Brand Building: Strengthen brand recognition through various marketing techniques.
- PR: Earn editorially-given links via media coverage.
- Content Marketing: Create and promote valuable content like videos, podcasts, ebooks, etc.
- Social Media: Optimize your brand’s profiles and share relevant content.
- Listing Management: Ensure your company information is consistent and verified across directories and review sites.
- Ratings and Reviews: Encourage reviews, monitor them, and respond where necessary.

Even though off-site SEO doesn't always directly affect rankings, it’s important to raise your brand’s visibility and establish trust wherever people may search for you.

In short, SEO is a comprehensive process that involves multiple components working together to ensure your website performs well, engages your audience, and builds long-term authority in your industry.

Some people have started to reframe "search engine optimization" (SEO) to mean "search experience optimization" or even "search everywhere optimization," emphasizing the broader scope of search across various platforms and experiences.

SEO Specialties

SEO also includes several subgenres that differ from traditional SEO. These specialized areas usually involve unique strategies and challenges.

Here are five key SEO specialties:

Ecommerce SEO: This involves optimizing category and product pages, faceted navigation, internal linking, product images, reviews, schema markup, and other factors to improve visibility in search engines for online stores.
Enterprise SEO: For large-scale websites or businesses, typically with millions of pages or extensive operations. Enterprise SEO often faces delays in implementing changes due to coordination with multiple stakeholders and teams, especially in large organizations with vast revenue and a broad digital presence.
International SEO: Focused on businesses that operate internationally, requiring optimization for multilingual and multiregional websites. This includes targeting international search engines like Baidu or Naver and handling issues like hreflang tags, localized content, and cultural nuances.
Local SEO: This type focuses on optimizing a website to rank well in local searches, including strategies for improving local listings, obtaining reviews, and enhancing visibility in local search results.
News SEO: News websites must prioritize speed, ensuring content is indexed quickly by Google and appears in prominent places like Google News, Discover, and Top Stories. It also involves specialized practices like managing paywalls, using structured data for news, and optimizing content for rapidly changing news cycles.

How Does SEO Work?

If you came to this page via Google, you likely searched for something along the lines of “What is SEO?”

This guide, hosted on Search Engine Land, a recognized authority in SEO, ranks highly due to its high-quality content, earned links, and its ongoing expertise since 2006. Over time, this content has gathered signals of trustworthiness, helping it stay in top search positions.

SEO works as a combination of several elements:

People: The team or individuals managing the SEO strategy, tactics, and execution.
Processes: The systems and workflows that make SEO efforts efficient.
Technology: The tools and platforms used to implement SEO.
Activities: The actual actions taken to improve search visibility.

Together, these factors help SEO efforts succeed.

Six Key Areas That Make SEO Work

Understanding How Search Engines Work:

To get found through search, you must understand how search engines process and rank pages. Traditional search engines, like Google, follow four primary stages:

Crawling: Search engines discover pages by following links and reading sitemaps.
Rendering: The engine processes how the page will display by interpreting HTML, JavaScript, and CSS.
Indexing: Search engines analyze the content of discovered pages and store it in their database, although not every page may be indexed.
Ranking: Search engines apply algorithms to assess a page’s relevance and quality to determine where it ranks for specific queries.

However, SEO for platforms like Google differs from optimizing for other platforms such as YouTube or Amazon, which each have their own specific ranking criteria and user behaviors.

Facebook vs. Twitter: How Different Platforms Rank Content

On platforms like Facebook, the factors influencing content visibility include engagement signals such as likes, comments, and shares, alongside the strength of a user's network. Twitter, on the other hand, prioritizes factors like the recency of posts, user interactions, and the credibility of the author. Furthermore, search engines have introduced machine learning algorithms to help surface relevant content, adding another layer of complexity to content ranking and making it more challenging to pinpoint the exact reason for performance fluctuations.

Researching: A Key Component of SEO

Effective SEO relies heavily on thorough research. Key types of research that can improve SEO performance include:

Audience Research: Understanding your target audience’s demographics, psychographics, pain points, and questions they need answers to is crucial for tailoring content effectively.
Keyword Research: Identifying and incorporating relevant keywords into your content is fundamental to ensuring your pages rank for high-demand terms.
Competitor Research: Analyzing competitors’ content and strategies will reveal their strengths, weaknesses, and opportunities for differentiation.
Brand/Business Research: Aligning SEO strategies with the specific goals of your brand or client ensures that efforts are directed toward meaningful outcomes.
Website Research: Performing SEO audits can uncover issues or opportunities on your website. Areas to audit include technical SEO, content, link profiles, and the E-E-A-T (Expertise, Authoritativeness, Trustworthiness) framework.
SERP Analysis: Understanding the search intent behind queries helps in crafting content designed to match user needs and increase chances of ranking.

Planning: The Long-Term SEO Strategy

An SEO strategy serves as a roadmap, setting clear goals and outlining how to achieve them. While the journey may evolve, the destination remains constant. The SEO planning process should include:

Defining goals (e.g., OKRs, SMART goals)
Setting expectations regarding timelines and milestones
Aligning KPIs and metrics
Determining whether projects will be handled internally, externally, or through a mix
Coordinating with stakeholders
Implementing tools and technologies
Structuring teams and determining budgets
Regularly measuring and reporting on results
Documenting strategies and processes

Creating and Implementing: Turning Research into Action

Once research is complete, it’s time to execute:

Create New Content: Guide the content team on what needs to be created based on research findings.
Enhance Existing Pages: Optimize current pages by updating content, adding internal links, and incorporating targeted keywords.
Remove Outdated Content: Eliminate underperforming content that doesn't contribute to SEO goals or provide value.

Monitoring and Maintaining: Keeping Your Website Healthy

Monitoring is vital for identifying issues early. Key factors to track include:

Declining traffic to important pages
Slow or unresponsive pages
Pages falling out of the index
Broken links
Site downtime or other technical problems

Analyzing and Reporting on SEO Performance

Without measurement, SEO can’t improve. Utilize tools like Google Analytics, Google Search Console, and other platforms to gather performance data. Regular reporting is essential to track progress and adjust strategies. Reports should be meaningful, comparing performance over time (e.g., year-over-year) and providing insights into areas for improvement.

SEO: An Ongoing Process

SEO is a continuous process. Changes in search engine algorithms, user behavior, and competition require constant attention. Websites evolve over time, content can become outdated, and SEO processes should always be refined for greater efficiency.

How SEO Evolves

SEO is dynamic and constantly evolving, partly due to its reliance on how humans interact with information on the web. The web, as a repository of information, is still relatively young, having only been around for a few decades. In comparison, institutions like libraries have existed for thousands of years, helping us understand how information is stored, accessed, and shared across time. Just as libraries have transformed, so too will the web and search engines. Google, for example, has only been in existence since September 1998, which gives us a sense of how much change is still to come.

The web and how we search for and retrieve information from it have transformed human memory and behavior in profound ways. We access search engines through various devices like computers, mobile phones, and smart assistants, and as technology evolves, so do our behaviors in how we use and apply it. This shift has significant implications for how search engines develop their features, which in turn impacts the evolution of SEO (Search Engine Optimization).

SEO's Evolution:

Adapting to Technology: SEO has had to evolve rapidly with the growth of technology, especially with the advancements in AI and mobile usage.
- AI-Driven Search Results: In recent years, AI has significantly changed how search engines display results. For example, Google's AI-driven overviews and Bing's generative search results are altering how search queries are handled.
- Mobile-First Indexing: With the rise of mobile phones, SEO practices shifted to ensure websites are optimized for mobile. As of 2021, 63% of Google searches in the U.S. occurred on mobile devices, leading to Google prioritizing mobile performance in its ranking algorithm.
- Speed and User Experience: The quality of internet services has improved, and so have user expectations. Slow-loading pages and poor user experiences are no longer acceptable, requiring websites to optimize for speed and a smooth user journey.
Adapting to Society: Beyond technology, societal changes also influence SEO practices.
- Macroeconomic Conditions: Economic factors such as recessions, war, or global crises like the COVID-19 pandemic can significantly affect consumer behavior and business operations. This necessitates changes in SEO strategies to align with shifting consumer priorities.
- The COVID-19 Pandemic: The pandemic was a turning point for SEO as it drastically changed how people interacted with businesses online. Companies had to quickly adapt their online marketing strategies to survive and thrive.

As both technology and society evolve, SEO must continuously adapt to stay relevant and effective. SEO is not only a marketing strategy but also a career path that has seen rapid growth and specialization in recent years.

The Growing SEO Market: The SEO services market is projected to grow from $75.13 billion in 2023 to $88.91 billion in 2024, with an annual growth rate of 18.3%, reaching $170 billion by 2028. This growth highlights the increasing demand for SEO expertise in an ever-changing digital landscape.

SEO is both a profession and a service. As a job, SEO offers numerous roles and specializations, allowing individuals to either "do" SEO or "be" an SEO expert. The field encompasses a wide range of tasks, including technical SEO, content optimization, and link-building strategies.

Getting Started with SEO: Unlike some traditional professions, SEO doesn't have a universally established educational path. However, there are numerous free and accessible resources to help newcomers understand SEO, including tools for keyword research, backlink analysis, and website performance monitoring (e.g., Google Analytics, Google Search Console, and Semrush).

Here are a few beginner-friendly tools:

Free Keyword Difficulty Checker
Free Keyword Ranking Checker
Free Backlink Research Tool
Free Website Traffic Checker
Free Competitor Analysis Tool

How to Learn SEO: To master SEO, staying updated on the latest news, strategies, and trends is essential. Regularly reading SEO resources, attending industry events, and participating in forums are great ways to expand your knowledge. Websites like Search Engine Land provide valuable insights, tips, and expert advice for SEO professionals.

SEO is constantly evolving with the introduction of new technologies, trends, and shifts in user behavior. Learning and adapting to these changes is crucial for anyone looking to succeed in the SEO field.

Search Engine Land offers a range of resources that cover specific aspects of SEO, which can help you deepen your understanding of the field. Their content is divided into several categories, including:

All SEO
Bing SEO
Content SEO
Ecommerce SEO
Enterprise SEO
Google: E-E-A-T
Google algorithm updates
Google Search Console
Google search features
Link building
Local SEO
News SEO
Technical SEO

Additionally, Search Engine Land offers tools like their Periodic Table of SEO Elements, which helps visualize the core components required for an effective SEO strategy. The interactive table emphasizes the need for ongoing effort and focus.

Google’s SEO Resources are also essential, with guides like:

Google Search Essentials, detailing technical requirements and best practices.
SEO Starter Guide, covering SEO basics.
Search Quality Evaluator Guidelines, explaining how Google assesses the quality of content through expertise, authority, and trustworthiness.

Developing SEO Skills: To enhance your skills, it’s recommended to experiment by building your own

websites, exploring different SEO techniques, and seeing what works. Learning SEO is a continual process that goes beyond basic tactics and includes understanding related skills.

You can also further your career by attending conferences like those hosted by Search Engine Land, such as the Search Marketing Expo (SMX) series, which features talks on various SEO aspects. SMX Advanced and SMX Next are particularly useful for deep diving into SEO topics.

Other methods to learn SEO include:

Websites, blogs, and publications
Books and ebooks
Videos, podcasts, and webinars
Conferences, meetups, and courses
Training programs and certifications
Social media groups and newsletters
Experts’ social media and online forums

However, it's important to stay cautious, as there’s a lot of outdated or misleading SEO information out there. The key takeaway is that SEO requires consistent work across all phases to improve visibility, clicks, authority, conversions, and ultimately, sales and revenue. There are no shortcuts or "universal truths"—it's about putting in the effort over time.