01 / Fundamentals
Search engine optimization (SEO) is the process of improving a website so search engines can discover, understand, and present its pages to people searching for relevant information, products, or services.
SEO combines several areas of website optimization, including technical performance, content quality, search intent, and the way pages are organized and connected. Understanding these fundamentals helps you make informed decisions about what to improve and how to measure progress.
What is SEO?
SEO stands for Search Engine Optimization. It involves making changes to your website and its content to improve its visibility in unpaid search results, also known as organic search.
When someone searches for a topic on Google or another search engine, the system identifies pages that may answer the query and orders them according to relevance and other ranking signals. SEO helps search engines understand your pages and helps visitors find useful information.
For example, a website selling hiking equipment might optimize a product category page for searches related to hiking backpacks. The page should provide relevant product information, use clear headings, and be accessible to search engine crawlers.
SEO is not a single technique or a guarantee of a particular ranking. It is an ongoing process of making a website easier to discover, understand, and use.
How organic search works
Organic search results are unpaid listings that appear in search engine results pages (SERPs). Search engines generally follow three main stages to make web pages available in search results.
The three stages of organic search
Simplified model. Each stage is covered in its own lesson.
These stages are connected, but they are not interchangeable. A page may be crawled without being indexed, and an indexed page may not appear prominently for a particular search query. The next lesson explains how crawling works in more detail.
Organic search and paid search
Search engine results pages can include both organic listings and paid advertisements.
Illustrative search results
Illustration only. Actual search results vary by query, location, device, and other factors.
The main difference is how visibility is obtained:
- Organic search: pages can appear without paying for each click. Visibility depends on search engine systems and factors such as relevance, content, and technical accessibility.
- Paid search: advertisers pay to participate in ad auctions and may be charged based on clicks or other campaign arrangements.
SEO focuses on organic visibility. Paid search can complement SEO, but advertising does not directly purchase organic rankings.
Search intent
Search intent is the reason behind a person's search query. Understanding intent helps you create pages that meet the needs of people searching for a particular topic. Four common types of search intent are:
| Intent | What the searcher wants | Example query |
|---|---|---|
| Informational | Learn or find an answer | How does SEO work? |
| Navigational | Reach a specific website or page | SiteAuditLint login |
| Commercial | Research options before deciding | Best SEO crawler for Windows |
| Transactional | Complete an action or purchase | Download SEO crawler |
A single topic can have different search intents. For example, someone searching for "SEO audit" might want to understand the process, compare auditing tools, or purchase an audit service.
Before creating a page, examine the query and consider what type of result would satisfy the searcher. A detailed tutorial may fit an informational query, while a product page may be more suitable for a transactional query.
Technical SEO
Technical SEO focuses on making a website accessible to search engines and usable for visitors. It includes the infrastructure and configuration that help crawlers discover, access, and process website content. Important areas include:
Crawlability
Ensuring search engine crawlers can access the pages you want them to discover. You can check crawlability for Google, Bing, and AI bots.
Indexability
Avoiding unintended directives or technical problems that prevent eligible pages from being indexed. See the guide to noindex issues.
Site structure
Organizing pages and internal links so that visitors and crawlers can navigate the website, and avoiding orphan pages with no internal links.
HTTP status codes
Identifying broken pages, redirect issues, and server errors. Start with finding and fixing broken internal links.
Mobile usability and performance
Making pages work well across devices and providing a responsive experience.
Canonicalization
Helping search engines understand which URL represents the preferred version of similar or duplicate content. Review common canonical tag issues.
A website can have useful content but still encounter search visibility problems if important pages are blocked from crawling, return errors, or are difficult to navigate.
A technical SEO audit can help identify these issues. A desktop crawler such as SiteAuditLint can be used to inspect website URLs, detect technical problems, and compare audit results over time.
Content and on-page SEO
Content is the information presented on a website. It helps visitors understand a topic and gives search engines material to interpret and potentially match with relevant queries. On-page SEO involves improving individual pages through elements such as:
- Page titles: descriptive titles that communicate the subject of each page.
- Headings: a clear hierarchy that organizes information into meaningful sections.
- Main content: accurate, useful information that addresses the visitor's needs. Watch for thin content and duplicate content.
- Internal links: links connecting related pages to support navigation and content discovery.
- Images and alternative text: relevant visuals with descriptive text where appropriate.
- Meta descriptions: page summaries that can help communicate what a search result offers.
Good content starts with understanding the audience and the questions they need answered. Adding keywords without providing useful information is not a substitute for satisfying search intent.
A page about choosing a hiking backpack should explain relevant differences in capacity, fit, and use cases rather than simply repeating the phrase "hiking backpack" throughout the text.
How the SEO fundamentals work together
SEO is not a collection of isolated tasks. Technical accessibility, relevant content, and search intent all contribute to how a website serves visitors and how search engines interpret its pages.
A simple SEO workflow
- Understand the search queryIdentify the audience, topic, and intent behind the searches you want to address.
- Create relevant contentDevelop a page that answers the searcher's needs with clear organization and useful information.
- Check technical accessibilityConfirm that important pages can be crawled, return appropriate status codes, and have a sensible internal linking structure.
- Publish and monitorCheck indexing and organic search performance, then identify areas that need improvement.
- Audit and improveReview technical issues, content quality, and changes in performance. Make improvements and measure the results over time.
Measuring SEO progress
SEO performance should be measured using multiple indicators rather than relying on a single ranking or traffic number.
| Metric | What it helps you understand |
|---|---|
| Organic clicks | How many visits arrive from unpaid search results |
| Impressions | How often pages appear in search results |
| Click-through rate (CTR) | The proportion of impressions that result in clicks |
| Average position | An aggregated indication of a site's search result position |
| Indexed pages | How many pages are included in a search engine's index |
| Conversions | Whether organic visitors complete important actions |
Tools such as Google Search Console can help monitor search impressions, clicks, indexing, and search performance. Website analytics tools can provide additional information about visitor behavior and conversions.
When evaluating progress, compare performance across suitable time periods and account for seasonal patterns, changes in demand, and updates to the website.
Key takeaways
- SEO improves a website's visibility in unpaid search results through technical, content, and organizational improvements.
- Search engines generally discover pages through crawling, process them for possible inclusion through indexing, and order results through ranking systems.
- Search intent helps determine what information or page format is appropriate for a query.
- Technical SEO supports crawling, indexing, and usability, while content helps satisfy the needs of visitors.
- SEO requires ongoing monitoring and improvement. Results are not guaranteed by completing a checklist.
Knowledge check
Ready to go further? Work through the technical SEO checklist, or learn what a website crawler is and how it works.