How Google discovers pages (crawling) in SEO Fundamentals - Step-by-Step Explanation

Introduction

Imagine trying to find every book in a huge library without a catalog. Google faces a similar challenge when it wants to find all the pages on the internet. It needs a way to explore and find new or updated pages so it can show them in search results.

Explanation

Starting with Known Pages

Google begins crawling from a list of known web pages, often popular or previously discovered sites. These pages act like starting points or seeds for the crawling process. From these seeds, Google looks for links to other pages to explore next.

Google starts crawling from a set of known pages to find more pages through links.

Following Links to Discover New Pages

When Google visits a page, it reads the links on that page to find other pages. These links act like paths leading to new content. By following links from page to page, Google can discover a vast network of web pages across the internet.

Google discovers new pages by following links found on already known pages.

Respecting Crawl Rules

Websites can tell Google which pages to crawl or avoid using special files like robots.txt or meta tags. Google respects these rules to avoid crawling pages that site owners want to keep private or unindexed. This helps Google focus on useful content.

Google follows website rules to decide which pages it can or cannot crawl.

Handling Updates and Changes

Google revisits pages regularly to check for updates or new content. It prioritizes pages that change often or are important. This way, Google keeps its index fresh and shows the latest information in search results.

Google revisits pages to keep its information up to date.

Real World Analogy

Imagine a mail carrier delivering letters in a neighborhood. They start with a list of houses they know, then follow paths and streets to find new houses. Some houses have signs saying 'No mail,' so the carrier skips those. The carrier also revisits houses that often change their mailboxes.

Starting with Known Pages → Mail carrier's initial list of houses to deliver mail

Following Links to Discover New Pages → Mail carrier following streets and paths to find more houses

Respecting Crawl Rules → Houses with 'No mail' signs that the carrier must skip

Handling Updates and Changes → Carrier revisiting houses that frequently change their mailboxes

Diagram

Diagram

┌───────────────┐
│ Known Pages   │
└──────┬────────┘
       │
       ▼
┌───────────────┐      ┌───────────────┐
│ Page A        │─────▶│ Page B        │
│ (Links to B)  │      │ (Links to C)  │
└──────┬────────┘      └──────┬────────┘
       │                      │
       ▼                      ▼
┌───────────────┐      ┌───────────────┐
│ Page C        │      │ robots.txt    │
│ (New Page)    │      │ blocks Page D │
└───────────────┘      └───────────────┘

Diagram showing Google starting from known pages, following links to discover new pages, and respecting crawl rules like robots.txt.

Key Facts

Crawling → The process Google uses to visit web pages and find new or updated content.

Seed Pages → Initial known web pages from which Google starts crawling.

robots.txt → A file websites use to tell Google which pages not to crawl.

Links → Paths on web pages that Google follows to discover other pages.

Recrawling → Google revisiting pages to check for updates or changes.

Common Confusions

Google crawls every page on the internet instantly.

Google crawls every page on the internet instantly. Google crawls pages over time, starting from known pages and following links; it cannot crawl the entire internet instantly.

If a page is linked, Google will always index it.

If a page is linked, Google will always index it. Even if a page is linked, Google may not index it if the site blocks crawling or if the page has noindex tags.

Summary

Google discovers web pages by starting from known pages and following links to new pages.

Websites can control crawling using rules like robots.txt to block certain pages.

Google revisits pages regularly to keep its search results up to date.

Practice

1. What is the main method Google uses to discover new web pages?

easy

A. Guessing URLs based on popular keywords

B. Manually adding pages submitted by users

C. Waiting for website owners to email URLs

D. Using automated crawlers that follow links from known pages

Solution

1. Step 1: Understand Google's discovery process

   Google uses automated programs called crawlers or spiders to find new pages by following links from pages it already knows.

2. Step 2: Compare options

   Only Using automated crawlers that follow links from known pages describes this automated crawling method. Other options describe manual or guessing methods which Google does not rely on.

3. Final Answer:

   Using automated crawlers that follow links from known pages -> Option D

4. Quick Check:

   Google uses crawlers = A [OK]

Hint: Remember: Google bots crawl links automatically [OK]

Common Mistakes:

• Thinking Google manually adds pages
• Believing Google guesses URLs randomly
• Assuming email submissions are main method

2. Which of the following is the correct term for Google's automated program that finds new pages?

easy

A. Crawler

B. Indexer

C. Ranker

D. Optimizer

Solution

1. Step 1: Identify Google's discovery tool name

   The program Google uses to find new pages by following links is called a crawler or spider.

2. Step 2: Eliminate other terms

   Indexer organizes pages after crawling, Ranker orders results, Optimizer improves site SEO. Only Crawler finds pages.

3. Final Answer:

   Crawler -> Option A

4. Quick Check:

   Google's discovery tool = Crawler [OK]

Hint: Crawler = program that finds pages [OK]

Common Mistakes:

• Confusing crawler with indexer
• Thinking ranker finds pages
• Mixing optimizer with crawler

3. If a website has no links from other sites and no sitemap, what will likely happen when Google tries to discover its pages?

medium

A. Google will find the pages quickly by guessing URLs

B. Google will automatically add the pages to its index

C. Google will not find the pages easily because there are no links or sitemap

D. Google will send a manual request to the website owner

Solution

1. Step 1: Understand how Google discovers pages

   Google relies on links and sitemaps to find new pages. Without these, discovery is difficult.

2. Step 2: Analyze options

   Google will not find the pages easily because there are no links or sitemap correctly states Google won't find pages easily without links or sitemap. Other options describe guessing, automatic adding, or manual requests which do not happen.

3. Final Answer:

   Google will not find the pages easily because there are no links or sitemap -> Option C

4. Quick Check:

   No links or sitemap = hard to find pages [OK]

Hint: No links or sitemap means hard for Google to find pages [OK]

Common Mistakes:

• Assuming Google guesses URLs
• Thinking Google adds pages automatically
• Believing Google contacts owners manually

4. A website owner notices Google is not discovering some new pages. Which of these is a likely cause?

medium

A. The new pages are not linked from any other page on the site

B. The website has a sitemap listing all pages

C. The pages have clear, descriptive titles

D. The website uses HTTPS protocol

Solution

1. Step 1: Identify why Google misses pages

   Google finds pages by following links. If new pages are not linked anywhere, crawlers cannot find them.

2. Step 2: Evaluate other options

   Sitemap helps discovery (B), titles help ranking (C), HTTPS helps security (A). Only lack of links (D) blocks discovery.

3. Final Answer:

   The new pages are not linked from any other page on the site -> Option A

4. Quick Check:

   No links = no discovery [OK]

Hint: Pages must be linked or in sitemap to be found [OK]

Common Mistakes:

• Thinking HTTPS affects discovery
• Confusing titles with discovery
• Ignoring importance of internal links

5. You want Google to discover a new section of your website quickly. Which combination of actions will help the most?

hard

A. Change the website's color scheme and add meta descriptions

B. Add internal links to the new pages and submit an updated sitemap

C. Remove old pages and increase page load speed

D. Use HTTPS and add social media share buttons

Solution

1. Step 1: Identify key factors for fast discovery

   Google discovers pages by crawling links and reading sitemaps. Adding internal links and updating sitemap helps crawlers find new pages quickly.

2. Step 2: Analyze other options

   Changing colors or meta descriptions (B) does not affect discovery speed. Removing old pages or speed (C) helps ranking but not discovery. HTTPS and social buttons (D) improve security and sharing but not crawling.

3. Final Answer:

   Add internal links to the new pages and submit an updated sitemap -> Option B

4. Quick Check:

   Links + sitemap = faster discovery [OK]

Hint: Links plus sitemap speed up Google discovery [OK]

Common Mistakes:

• Focusing on design changes instead of links
• Ignoring sitemap importance
• Confusing ranking factors with discovery