In the robots meta tag, the value “all” indicates the default behavior for search engine crawlers. When you use “all” as the content attribute value in the robots meta tag, it essentially means “index, follow.”
Here’s what each part of “all” means:
Index
It instructs search engines to include the page in their index, which means the page can potentially appear in search results when relevant to user queries.
Follow
It allows search engine crawlers to follow and crawl all the links present on the page. This means the search engine can discover and index other pages linked from the current page.
Essentially, by using “all” in the robots meta tag, you explicitly state that the page should be indexed, and crawlers are allowed to follow and index all links on that page.
However, it’s worth noting that using “all” in the robots meta tag is typically unnecessary since it represents the default behavior. By default, search engines assume “index, follow” if there is no robot meta tag or the tag’s content attribute is not specified.
For this reason, you will rarely see “all” used in practice, as it doesn’t provide any additional instructions beyond the default behavior of search engines. Most commonly, specific directives like “noindex” or “nofollow” are used in the robots meta tag to override the default behavior for specific pages or content.