Nofollow is a HTML credit esteem used to teach web crawlers bots that a hyperlink ought not impact the connection target's positioning in the internet searcher's list. It is planned to decrease the viability of specific sorts of web crawler spam, in this way enhancing the nature of web index comes about and keeping spamdexing from happening in any case. This is an idea presented by Matt Cutts and Jason Shellen in the year 2005.