Search Engine Optimization (SEO)

Quick answer: Search engine optimization (SEO) is the practice of improving a website and its content so that it ranks higher in organic (non-paid) search engine results pages (SERPs) for relevant queries. SEO works by aligning a website’s technical structure, content quality, and external authority signals with the criteria search engines use to determine which pages best answer a given search query. Higher organic rankings produce more traffic without ongoing paid media spend.

What Is SEO?

Search engine optimization (SEO) is the discipline of making websites and content more visible in organic search results. When a person types a query into Google, Bing, or another search engine, the engine returns a ranked list of pages it considers most relevant and authoritative for that query. SEO is the set of practices designed to make a page more likely to appear at the top of that ranked list for queries relevant to the business.

SEO is distinguished from paid search advertising (PPC) in that organic rankings are earned rather than purchased. A page that ranks first in organic results for a high-volume query will receive that traffic for as long as it maintains its ranking, without ongoing per-click media spend. This makes SEO a compounding investment: rankings and traffic build over time, and the cost per visitor declines as the content asset matures.

The downside of organic SEO relative to paid search is time. A new page published today may take three to twelve months to rank for competitive queries, while a paid search ad can begin driving traffic within hours of launch. For this reason, most marketing programs use paid search for immediate demand capture and SEO for long-term audience and traffic building.

The Three Pillars of SEO

SEO professionals typically organize their work around three categories: technical SEO, on-page SEO, and off-page SEO (link building).

Technical SEO addresses the structural and performance characteristics of the website itself. Core technical SEO factors include page speed and Core Web Vitals performance, mobile responsiveness, crawlability (the ability of search engine bots to discover and index the site’s pages), HTTPS security, structured data markup, and canonicalization (preventing duplicate content from diluting ranking signals).

On-page SEO addresses the content and HTML elements of individual pages. On-page factors include keyword research and targeting (selecting the specific queries a page is designed to rank for), content quality and depth, title tags and meta descriptions, header tag hierarchy (H1, H2, H3), internal linking structure, and image optimization including alt text.

Off-page SEO addresses the external signals that indicate a page or site’s authority. The primary off-page signal is backlinks, specifically links from other websites pointing to the page. Search engines interpret links from authoritative external sites as votes of confidence in the linked page’s quality and authority. Building a strong backlink profile through digital PR, content partnerships, and link-earning content remains one of the most impactful SEO activities for improving competitive rankings.

SEO and AI Search

The emergence of large language model-powered search features, including Google AI Overviews, Perplexity, and ChatGPT search, is changing how SEO is measured and optimized. When search engines surface AI-generated answers at the top of the SERP, some users get their answer without clicking through to any website, reducing the traffic that would historically have flowed to high-ranking pages. This phenomenon, sometimes called zero-click search, means that raw organic traffic is a less complete measure of SEO value than it was previously. Visibility in AI-generated answers (sometimes called AEO or answer engine optimization) is an emerging extension of traditional SEO.

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As search engines continue to evolve, the fundamentals of SEO remain consistent: create content that answers specific user questions thoroughly, earn citations from credible sources, and ensure the site is technically accessible for crawling and indexing. Brands that treat SEO as an ongoing editorial process rather than a one-time technical project consistently build durable organic visibility. Monitoring rankings, traffic, and crawl health on a monthly cadence allows teams to detect algorithmic shifts and adapt before rankings erode significantly.

Sources

  1. Google. (2024). How Search Works. Google LLC. https://www.google.com/search/howsearchworks/
  2. Moz. (2024). Beginner’s Guide to SEO. Moz Inc. https://moz.com/beginners-guide-to-seo
  3. Semrush. (2024). State of Search Report. Semrush. https://www.semrush.com/blog/state-of-search-2023/
  4. Ahrefs. (2024). SEO Statistics. Ahrefs Pte. Ltd. https://ahrefs.com/blog/seo-statistics/
  5. Backlinko. (2024). Google CTR Statistics. Backlinko. https://backlinko.com/google-ctr-stats
  6. Search Engine Journal. (2024). State of SEO. Search Engine Journal. https://www.searchenginejournal.com/state-of-seo/
  7. BrightEdge. (2024). Organic Channel Share Report. BrightEdge Technologies. https://www.brightedge.com/resources/research-reports
  8. HubSpot Research. (2024). State of Marketing Report: SEO section. HubSpot Inc. https://www.hubspot.com/state-of-marketing
  9. Google Search Central. (2024). Google Search Essentials (formerly Webmaster Guidelines). Google LLC. https://developers.google.com/search/docs/essentials
  10. Conductor. (2024). Organic Marketing Benchmark Report. Conductor LLC. https://www.conductor.com/learning-center/
  11. SparkToro. (2024). Zero-Click Search Study. SparkToro. https://sparktoro.com/blog/
  12. Search Engine Land. (2024). Core Web Vitals and SEO. Search Engine Land. https://developers.google.com/search/docs/appearance/core-web-vitals

Written by the My Marketing File editorial team. This article is reviewed periodically for accuracy.