Crawlers, also known as web crawlers or spiders, are automated programs designed to browse the internet and index content from websites. They systematically visit web pages, following links to discover new content and gather information, which is then used by search engines like Google to improve search results. These programs play a crucial role in maintaining the relevance and accuracy of search engine databases. By continuously scanning the web, crawlers ensure that the latest information is available to users, helping them find what they need quickly and efficiently.