How search engines work: Crawling, indexing, and ranking

1. Introduction

• Role of search engines in daily life (Google, Bing, Yahoo).
• Example: “best dosa near me” vs. “how to fix a leaking tap.”
• Three main steps explained with analogy:
  • Crawling → Discovering new books.
  • Indexing → Cataloguing the books.
  • Ranking → Deciding which book is best for the question.
• Importance of understanding this process for SEO.

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2. Crawling: How Search Engines Discover Content

• Definition: Bots (spiders) scan the web for new or updated content.
• Process:
  • Following links from page to page.
  • Reading XML sitemaps.
  • Rendering JavaScript (with limitations).
• Key Factors Affecting Crawling:
  • Site structure & internal linking.
  • Robots.txt and meta tags.
  • Crawl budget based on site authority.
  • Canonical tags for duplicates.
• Example: New blog linked on homepage gets crawled faster.
• Tools:
  • Google Search Console (Crawl Stats, URL Inspection).

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3. Indexing: How Search Engines Understand and Store Content

• Definition: Process of analyzing and storing crawled pages in the index.
• What Engines Look At:
  • Content relevance & keyword usage.
  • Meta tags (title, description).
  • Structured data/schema markup.
  • Media elements (alt text, captions).
• Why Pages Do not Get Indexed:
  • Duplicate/thin content.
  • Blocked by robots.txt or no index.
  • Slow-loading pages.
  • Spammy or low-quality content.
• Example: Product page with unique description + proper alt text more likely to be indexed.
• Modern Note: Mobile-first indexing (mobile version prioritized).
• Tools:
  • site:example.com operator.
  • Google Search Console (Index Coverage Report).

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4. Ranking: How Search Engines Deliver the Best Results

• Definition: Ordering indexed results based on query relevance.
• Key Ranking Factors:
  • Relevance to query & intent.
  • Content quality (original, helpful, trustworthy).
  • E-E-A-T (Experience, Expertise, Authoritativeness, Trust).
  • User experience (speed, mobile, navigation).
  • Backlinks and authority.
  • Content freshness.
  • Engagement signals (CTR, dwell time).
• Example: Query “best smartphones under 15000 in India.”
• Local Ranking Factors:
  • Proximity, Google Business Profile, reviews.
• Ranking Updates:
  • Core Updates, Helpful Content Update, Spam Updates.

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5. How Crawling, Indexing, and Ranking Work Together

• Flow: Crawling → Indexing → Ranking → SERP Display → User Interaction → Feedback loop.
• Importance of each step:
  • No crawling → Not discovered.
  • No indexing → Not stored.
  • No ranking → Not visible.

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6. Challenges Search Engines Face

• Duplicate content.
• Cloaking/hidden text.
• Spammy backlinks.
• Heavy JavaScript rendering issues.
• Ongoing updates to handle abuse.

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7. The Future of Search Engines

• AI-driven systems (BERT, RankBrain, Gemini).
• Voice and visual search growth.
• Zero-click searches and direct answers.

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8. Conclusion

• Crawling, Indexing, Ranking = foundation of visibility.
• Good SEO = support each stage:
  • Crawlable site structure.
  • Index-worthy unique content.
  • Ranking signals like backlinks, trust, speed.
• Final takeaway: Without mastering these basics, no SEO strategy works.

1. Introduction

Let me ask you something. When was the last time you Googled something? Was it ‘best dosa near me’ when you were starving in Bangalore traffic? Or maybe ‘how to fix a leaking tap’ after your bathroom pipe burst in the middle of the night in Delhi? Within seconds, Google gave you answers a restaurant, a plumber, or a YouTube video.

It feels magical, right? But I will tell you the truth: nothing about it is magic. It is science, process, and a lot of background work. What looks like an instant result is three important steps. These steps work in order: Crawling, Indexing, and Ranking.

Think of it like a giant library.

• Crawling is when new books are discovered.
• Indexing is when they are catalogued properly.
• Ranking is when the librarian decides which book to hand to you first.

I always tell my students. If you run a business online, you cannot ignore this process. It does not matter if it is a saree shop in Surat. It could even be a small tuition center in Lucknow. The rules are the same. It is the foundation of SEO. And I have seen, time and again, how people who ignore this struggle to get even a single visitor from Google.

2. Crawling: How Search Engines Discover Content

Crawling is like Google little bots roaming around, trying to see what is new on the internet. They jump from one link to another, they check sitemaps, and they even try to make sense of JavaScript heavy sites.

But here is where many Indian businesses get it wrong. They build beautiful websites, spend lakhs on design, and then forget the basics navigation. If crawlers cannot reach your pages, your audience never will.

I remember working with a grocery startup in Hyderabad. Brilliant idea they had a blog on healthy millet recipes. But for weeks, their blog posts did not show up on Google. The founders were panicking, thinking SEO does not work. When I checked, the issue was simple: none of those blog posts were linked from the homepage. Google bots had no road to travel.

We fixed the internal linking, submitted a sitemap in Google Search Console, and within days, the posts appeared on Google. I still remember the joy on their faces when their first millet recipe started ranking for “jowar roti health benefits.”

Lesson: If Google cannot find your page, your customers never will.

3. Indexing: How Search Engines Understand and Store Content

Now, crawling is just discovery. Indexing is the real test. This is when Google decides whether your page is worth storing in its giant database.

When I teach, I compare it to an exam. You might write something on your answer sheet, but unless the examiner finds it relevant and neat, you do not get marks. Similarly, Google looks for:

• Content relevance (are you answering what people are searching for?),
• Meta tags,
• Structured data,
• Alt text for images,
• And most importantly, originality.

Here is a painful story. An electronics store in Mumbai came to me once. They were complaining that half their products were not showing on Google. When I checked, I found they had copy-pasted product descriptions directly from their supplier. Word for word. Google treated that as duplicate content and refused to index them.

I asked them to rewrite everything in their own words. I told them to use simple English. I also asked them to add FAQs like, “Will this mixer grinder work on inverter?” Within two months, indexing improved, traffic started growing, and yes sales followed.

And do not forget, with mobile first indexing, Google now looks at your mobile site first. A Delhi coaching centre lost almost all its rankings because their mobile version had half the content of the desktop one. They thought nobody reads long details on phones, so they cut it short. Big mistake.

Lesson: If your page is not indexed, it is invisible. And invisible pages do not make sales.

4. Ranking: How Search Engines Deliver the Best Results

Now comes the big question students always ask me: “Sir, once Google has my page, how do I get to the top?”

That is ranking.

Google uses hundreds of factors, but lets simplify:

• Are you answering the exact query?
• Is your content original, useful, and trustworthy?
• Do you show experience and expertise (E-E-A-T)?
• Is your site fast, mobile friendly, and pleasant to use?
• Do other websites trust you enough to link back?
• And is your content fresh and updated?

Look at the keyword: best smartphones under 15000 in India. Almost always, you will see sites like 91mobiles, Gadgets360, or NDTV Gadgets. Why? Because they keep updating their content, they provide comparisons, and users trust them.

Now I am going to do local research. A kirana store in Pune once came to me, frustrated that a bigger supermarket kept outranking them. We optimized their Google Business Profile. We encouraged loyal customers to leave reviews. We added real pictures of their store. Within three months, they started appearing above the big chain for “grocery shop near me.” The owner told me, with tears in his eyes, that foot traffic had doubled. That is the power of ranking done right.

And lets be real: Google updates can feel brutal. Many Indian bloggers I know cried after the Helpful Content Update, when their traffic dropped overnight. But those who doubled down on writing genuinely helpful content do not fluff bounced back.

Lesson: Ranking is not about tricking Google. It is about proving you deserve to be at the top.

Crawling → Indexing → Ranking → Visibility → Customers.

Miss one step, and you are invisible. Get it right, and you will not only rank you will reach real people searching for real solutions you can provide.

And trust me, there is no greater feeling. Seeing a small business owner, whether it is a saree seller in Surat. A kirana in Pune, light up when their first customer walks in and says, “I found you on Google.

5. How Crawling, Indexing, and Ranking Work Together

I will be honest with you. Most people think once they build a website, Google will automatically send traffic. That is not how it works.

Crawling → Indexing → Ranking → SERP Display → User Interaction → Feedback loop.

Let me tell you a story. One of my closest friends in Hyderabad, Sravani, runs a small handloom saree store. She finally decided to put her catalogue online. She was excited. She thought people searching for ‘Pochampally sarees online’ would instantly find her. But weeks went by, and not a single online order came.

When she called me, I took a look. Guess what? Google’s crawlers could not even reach half her saree pages. The reason was her internal links were broken. Even worse, the few pages that crawled were not being indexed. This happened because she had copy-pasted supplier descriptions word for word. To Google, her site looked like a duplicate of dozens of others.

We rolled up our sleeves. She rewrote every product description in her own words. She also added her personal story about sourcing sarees from weavers. We fixed the broken links. Then we submitted a clean sitemap through Google Search Console.

Within weeks, things turned around. Her sarees started showing up on search results. Today, she gets orders from Chennai, Delhi, even as far as Jaipur. She told me once, “I never thought a weaver’s work from my little shop could reach so far.” And that moment hit me hard. This is the power of getting crawling, indexing, and ranking right.

6. Challenges Search Engines Face

Now, do not think search engines have it easy. They are not magical beings. They face real problems, especially in India.

• Duplicate content: I see this all the time. Many Indian ecommerce sites simply copy supplier text. Google struggles who should it trust as the original?
• Cloaking/hidden text: A coaching center in Delhi once tried to trick Google. They did this by stuffing hidden keywords. It worked for a short time, but eventually, their rankings crashed.
• Spammy backlinks: A small institute in Pune proudly told me they bought 5,000 backlinks for cheap. Within months, they were penalized. They came back to me asking, “Sir, why did our traffic disappear?” That is the risk of shortcuts.
• Heavy JavaScript: Startups love fancy websites with animations. But I have seen Google fail to crawl them properly. Pretty design does not always mean SEO friendly.
• Constant updates: Do you remember when several Indian travel websites dropped in rankings? It happened after a Google core update. That was Google cracking down on thin, repetitive content. Many businesses panicked overnight.

7. The Future of Search Engines

Search is changing fast, and India is right in the middle of it.

• AI-driven search: Tools like BERT and Gemini are smarter now. If you search ‘railway ticket refund process after cancellation’, Google gives an answer. It is detailed step by step. It does not just show random links.
• Voice search: My nephew in Vijayawada does not type on Google. He just says in Telugu, “Best dosa near me”. Voice search is exploding in regional languages.
• Visual search: A college student I know in Bangalore spotted a kurta in a cafe. He clicked a photo of it. Then he searched for it on Google Lens. Finally, he bought the same design online. That is how shopping looks today.
• Zero click searches: Cricket fans do not even click anymore. Search “India vs Pakistan score” and the result is right there. Businesses need to understand that clicks are not the only measure of visibility now.

The bottom line: search is becoming more human, more natural, more conversational.

8. Conclusion

If Google cannot crawl your site, it cannot index it. If it cannot index it, you will never rank.

Sravani’s saree business is living proof. She did not spend lakhs on ads. She did not hire a big agency. She just fixed the basics clear links, original descriptions, and a sitemap. That is it. And it changed her business.

Here is what good SEO really means:

• Make your site crawlable (simple structure, working links).
• Create index worthy content (unique, mobile friendly, relevant).
• Strengthen ranking signals (quality content, backlinks, trust, speed).

I tell every student this: No fancy ad campaign or viral reel will help you if Google cannot even list your site. SEO starts with the basics crawling, indexing, and ranking. Get that right, and you will build something that lasts.