Crawlers (webbot, web crawler, search engine bot, bot) are software programs that independently search the Internet. They read web pages, their contents and links in order to store, analyze and index them. The best known are the crawlers of large search engines. Smaller crawlers with comparable functions can be used for clouds or personal websites. Exactly what steps the program performs is determined before the crawl begins. The name comes from the first publicly usable search engine called WebCrawler and refers to the programs' approach. They systematically work their way through the Internet from link to link until they either encounter a page with no links or a loop.
Crawler sind die Voraussetzung dafür, dass es SERPs gibt. Die ersten Versionen von Suchmaschinen entstanden Anfang der 90er-Jahre. Sie dienten zunächst dem schnellen Auffinden von Dateien und Ordnern in FTP-Verzeichnissen. Später durchsuchten die Programme Datenbanken, Archive und das Internet nach Informationen. Die Idee, Suchmaschinen-Ergebnisse nach Relevanz zu sortieren, stammt von den Entwicklern von Google.
With the growing importance of the Internet for marketing purposes, the ranking of one's own Internet presence has become increasingly important. Search engine optimized pages are a decisive factor in presenting one's own company, products and services. In order for potential customers to see company pages displayed high up in a query, the search engine algorithm must classify the pages as up-to-date, relevant and reliable.
In order to place a website optimally on the Internet, it must be crawled and indexed by the leading search engines. Crawlers only invest a limited amount of time in a website, the so-called crawl budget. Es is important to offer the program the best possible technical conditions and an optimized structure in order to have as much of a website captured as possible. Text length, keyword distribution, external as well as internal links play a role in the ranking. How important the individual factors are depends on the current search engine algorithm and may change with the next update.
The activity of crawlers on your own website can be controlled. Es offers the possibility to block unwanted programs. Restricting the activities of a web crawler with noindex or nofollow via the Robots.txt file can be useful. These URLs are then not taken into account in the overall evaluation.
The exact interpretation and analysis of crawler behavior is one of the most important tasks in technical SEO and belongs to the basic SEO services. By using special SEO software, the crawling behavior of the bots can be recreated. This is the basis for SEO support and the development of an SEO strategy.