How Indexing Works
After Google has found and processed your webpage, the search engine determines what your webpage is about and categorizes it accordingly. This process of identification and categorization is called indexing. After a page is indexed, the page is stored in the Google Index which is a large database of a massive network of servers.
Robot meta directives include “meta tags” and “meta descriptions.” These are instructions that help Google understand how to crawl and index your web content.
Google can’t easily capture the meaning and contents of things like images, videos, and infographics, so webmasters and content creators can add concise descriptions to the code via meta tags to enable Google to quickly understand what that content (image, video, etc.) is about and correctly index it into image results, video results, or other types of search results.
Accessibility SEO: Meta tags also help users that require technologies like screen readers to access the content of your site. These assistive technologies read meta tags to the user to help them understand the contents of the image and contextualize it with the rest of the webpage content.
How to Control Indexing with Robot Meta Directives
You can also use meta tags to give crawlers directions on how to index your content. None of these directives are case-sensitive. Here are some of the most common indexation directions you can give search engines via meta tags:
- “noindex”and “index” - these tell crawlers whether to index a page or not.
- “nofollow” and “follow” - these tell crawlers whether to follow a link to another page or not.
- “noimageindex” - tells a crawlers not to index an image
Meta descriptions help Google to quickly understand the overall purpose of a web page and properly index it. Meta descriptions are also often displayed to users in the search result (under the blue link) to give them a preview of what the webpage will be about before they actually click on the page.