How Search Works | Indexing
Indexing Is pivotal in ensuring that the information retrieved during crawling is organized, understood, and made accessible for users. Let's explore how indexing works and why it is vital for search engines.
In our previous post, we covered how crawling works. Just as a refresher this is the initial step in how Google discovers and downloads new and updated web pages.
What happens after this data is downloaded and “digested” is called Indexing.
What is Indexing?
Here is the definition by Google themselves:
“Google analyzes the text, images, and video files on the page, and stores the information in the Google index, which is a large database” – Google for Developers
Indexing is the process that comes after crawling and rendering a web page.
It involves analyzing and processing the content of the page to determine what it contains and how it should be cataloged.
Without indexing, search engines would struggle to understand the nature of the pages, making it difficult for users to find relevant information.
The Mechanics of Indexing
1.Parsing HTML and Fixing Semantic Issues
Search engines like Google examine web page code to verify its structure and content.
The <head> section, containing essential page metadata, is particularly important.
Incorrect or unsupported HTML tags can disrupt this section, preventing Google from accessing crucial information needed for indexing and search results.
2. Content Analysis
Search engines like Google process various page elements, including text, images, and metadata, to determine the page’s topic and purpose.
This categorization helps match user searches with relevant results.
3. Duplicate Detection and Canonicalization
When multiple web pages have identical or nearly identical content, Google determines the most authoritative version, known as the canonical page.
Only this preferred version is typically displayed in search results. However, Google may show alternative versions in certain situations.
4. Signal Calculation
Search engines use numerous factors, or signals, to evaluate a webpage’s importance and suitability for search results.
These signals range from simple website owner-provided cues to complex algorithms determining overall web prominence.
Google’s search algorithm is incredibly complex and proprietary. While they provide general guidelines for webmasters, the exact details of how ranking signals are calculated remain a closely guarded secret.
This intentional opacity is meant to prevent search engine optimization (SEO) from becoming solely reliant on manipulating known factors, which could ultimately harm the user experience.
5. Duplicate Clustering
To manage duplicate content efficiently, Google groups together web pages with highly similar content into clusters.
Within each cluster, one page is designated as the canonical version, representing the group in search results.
This approach helps Google present users with the most relevant and authoritative version of the content.
6. Index Selection
After evaluating a webpage’s quality and relevance based on various signals, Google decides whether to include it in its vast search index.
This massive database, spread across countless computers, stores information about billions of web pages, ready to be searched and presented to users.
Only pages deemed valuable and relevant are granted a place in the index.
7. Why Indexing Matters
Indexing is the backbone of a search engine’s ability to deliver relevant search results.
By thoroughly understanding and categorizing web pages, Google ensures that users can find accurate and helpful information quickly.
The indexing process also helps maintain the quality of search results by filtering out duplicate and low-quality pages.
Fun Fact
Stripping away the SEO jargon, indexing is essentially a database technique for organizing vast amounts of information.
It does so in order to maximize query performance.
By structuring data efficiently, search engines like Google can rapidly find and deliver relevant results.
This lightning-fast performance is a key reason for Google’s dominance and user satisfaction.