A piece of code that lets you control how a search engine bot will crawl and index your web page content. The default value is “index, follow”, meaning the SE bot will both index your page and follow all the links pointing away from it.
There are other values like:
- noindex – prevent the SE bot to index your page
- nofollow – instruct the SE bot to not follow any links on this page
- nosnippet – a description will not be displayed in the SERP listing (only for Google)
- noimageindex – prevents the images from your page being displayed in the image search
- noarchive – a cached copy of your page will not be stored or displayed in the SERPs
- and more