The noindex tag is a type of meta tag that you can insert into the HTML code of a website so that it instructs search engines not to index that site. In simple words, even if other sites have links to it, it will never show up on search engine results pages (SERPs). The noindex tag is also an extremely handy way to label pages with duplicate content, those that are in development, or simply pages that should not be viewed by the public, period. The noindex tag assists webmasters in controlling what is crawled by search engines so that they only appear in their results if they are worth it and offer something of value to the public.