What is SEO? Search engine optimization explained
SEO (search engine optimization) is the work of making a website’s pages rank in Google, Bing and other search engines for the searches its customers make, without paying for each click. SEO is also the base that AI search builds on: assistants mostly quote pages that already rank. This guide covers how search engines rank pages, a 16-point checklist and the numbers to track.
By Sinan Yorulmaz · Updated 10/30/2026
- Term
- SEO
- Stands for
- Search Engine Optimization
- Also called
- Organic search, search marketing
- Where it applies
- Google, Bing, Yandex, DuckDuckGo
- Measured by
- Rankings, organic clicks and the conversions they bring
SEO, AEO and GEO compared
The three build on each other. SEO gets the page into the index and the results; AEO and GEO decide whether it becomes the answer.
| SEO | AEO | GEO | |
|---|---|---|---|
| Goal | Rank a page in the search results | Be the one direct answer to a question | Be mentioned, recommended and cited in generated answers |
| Where | Google and Bing results | Featured snippets, voice assistants | ChatGPT, Gemini, Perplexity, Claude, AI Overviews |
| Success looks like | Position, clicks | Owning the snippet | Mention rate, citations, share of voice |
| Main levers | Relevance, links, technical health | Short, structured answers | Quotable facts, brand mentions on other sites, AI crawler access |
| How you measure | Rank tracker, Search Console | Rank tracker with SERP features | Repeated questions in each assistant, AI referrals, crawler logs |
How a search engine ranks a page
Google describes the same three stages in its own documentation, plus the moment a result is shown. A page can fall out at any of them.
- 1
Crawling
A crawler such as Googlebot finds the page through links and sitemaps and downloads it, if robots.txt allows it.
- 2
Indexing
The engine renders the page, works out what it is about and stores it. Duplicates, noindex tags and thin pages are left out.
- 3
Ranking
For each search it orders the indexed pages by relevance, quality, links from other sites, freshness and page experience.
- 4
Serving
The result shows a title and a snippet. A clear title and description decide whether people click, even at the same position.
SEO checklist
Sixteen checks in four groups. Start with the technical basics: a page that cannot be crawled or indexed cannot rank.
Technical
- Important pages return 200, are allowed in robots.txt and listed in the sitemap. Robots.txt checker →
- Each page has one canonical address; old addresses redirect with a single 301. Redirect checker →
- The site loads fast on mobile and passes Core Web Vitals (LCP, INP, CLS). Core Web Vitals checker →
- Language versions point to each other with hreflang. Hreflang checker →
On the page
- Every page has a unique title and meta description that match the search it targets. Meta tag checker →
- One H1 and clear subheadings follow the questions people ask.
- Images have descriptive alt text and modern formats.
- Structured data describes the organization, products, articles and FAQs. Schema markup checker →
Content
- Each page targets one main search and answers it better than the pages ranking now.
- You know which searches are close to page one (positions 11–20) and improve those pages first.
- Two pages never compete for the same search; you merge or differentiate them.
- Pages show an author, a date and real experience, and are updated when facts change.
Links and authority
- Internal links point from strong pages to the pages you want to rank, with descriptive anchor text.
- Other relevant sites link to you because they quote your data, tools or guides. Website authority checker →
- You watch new and lost backlinks and fix broken links pointing to you.
- Your business details are the same on your site, Google Business Profile and directories.
How to measure SEO
Rankings change by device, location and day. Track a fixed set of searches over weeks and judge changes against the same period before.
Rankings
Your position for each target search, by country and device.
Visibility
The share of possible clicks your rankings capture, weighted by search volume.
Clicks and impressions
Real Google data from Search Console, per page and per search.
Click-through rate
Clicks divided by impressions; low values point to weak titles and descriptions.
Indexed pages
How many of your important pages Google has actually indexed.
Conversions
Sign-ups, sales or leads from organic visits in your analytics.
Searvia tracks Google rankings every day, audits your site, connects Search Console and Analytics, finds searches close to page one and can apply fixes such as titles and redirects on your site. See pricing →
What not to do
Tactics that worked years ago now get pages ignored or penalised.
- Buying links or joining link schemes: Google’s spam policies cover them and manual actions remove the gains.
- Mass-producing pages with no new information, written by people or by AI.
- Hiding text or showing search engines different content than visitors.
- Stuffing the same keyword into every heading and sentence.
- Expecting results in days: most changes need weeks before they show in rankings.
Read next: Technical SEO audit · Google rank tracker · Schema markup · GEO vs SEO · What is GEO?
SEO questions
Technical fixes can show within days of the next crawl. New content and links usually take three to six months to reach stable positions, longer in competitive markets.
Yes. AI assistants and Google AI Overviews mostly quote pages that already rank, so SEO is the entry ticket to AI answers as well as to the classic results.
SEO earns unpaid positions in the results. SEM usually means paid search ads; the clicks stop when the budget stops.
For competitive searches, yes: links from relevant sites remain one of the strongest signals. For niche or local searches, good pages and a complete business profile can be enough.
The part of SEO that makes a site easy to crawl, render and index: status codes, redirects, canonicals, sitemaps, speed, mobile layout and structured data.
Yes. Most of the work is fixing technical issues, writing pages that answer real searches and earning a few good links. Tools show what to fix first.
Find what holds your site back
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