In the broadest sense, the term „index“ refers to an organized directory or register that enables quick access to specific information. Its function is to make it possible to find and retrieve large amounts of data efficiently. It can be thought of as a comprehensive library system that catalogs exactly where which books and articles can be found.
The search engine index
In the area of Search engine optimization (SEO) and the Performance marketing the search engine index is of central importance. It is a gigantic, decentrally organized database in which search engines such as Google, Bing or DuckDuckGo store billions of web pages that contain their Web crawler have discovered and analyzed. Only content that is listed in this index can be included in the Search results (SERPs) appear. The index therefore acts as the source of all potential search results, from which the search engine selects and ranks the most relevant answers to a user query.
The indexing process involves several steps: First, the search engine bots crawl the internet to find new or updated websites. The content of these pages is then analyzed to understand their relevance, keywords and structure. This extracted information is then stored in the search engine index. This process is dynamic; the index is continually updated to reflect the constant changes on the internet. An up-to-date and comprehensive index is crucial for the quality and timeliness of search results.
Control and check indexing
It is essential for website operators to monitor the indexing status of their content and control it if necessary. Tools such as the Google Search Console offer detailed insights into the index coverage of a website. Here you can see which pages are indexed, what problems there are with indexing and how often Google has visited the page. For example, the message „Crawled - currently not indexed“ can mean that the page is known, but has not (yet) been included in the main index for quality reasons or lack of relevance.
There are also ways to specifically influence indexing. The use of the noindex-meta tags in the <head>-area of an HTML page instructs search engines not to include this specific page in their index. This is useful for pages such as internal search results, shopping cart pages, thank you pages or test environments that should not appear in the public search results. Alternatively, the robots.txt-file to keep crawlers away from certain directories or files, which indirectly prevents indexing because the content is not crawled in the first place.
