Noindex is an instruction that excludes a page from the search engine index, although it remains accessible to visitors. It is written as a meta tag in the page header or in the server response header. Nofollow, on the other hand, tells the robot not to follow links on the page, or is applied to an individual link. It is worth excluding pages without standalone value from the index – internal search results, thank-you pages, login and user sections, test versions, and duplicate listings. A condition for it to work is that the robot must be allowed to crawl the page, meaning it must not also be blocked in the robots.txt file. After deployment, it is worth checking in webmaster tools whether the page has actually been removed from the index. For larger websites, it is worth keeping a list of sections that are deliberately excluded from the index, so that they are not mistaken for an error during a later audit.
See also: Robots.txt, Index bloat, Thin content.
