RSS:RSS also knew as “Rich Site Summary” or “Real Simple Syndication”. It’s a basically used in an XML document for sharing contents or information with different websites.

Reciprocal Link: Reciprocal link refers to the exchange links between two websites with each other. It’s a very successful in achieving high search engine rankings, but its now of less established value.

Robots.txt: Robots.txt refers to a file used to reject some or all robots as of crawling some or all the pages or directories on a website. This file should be located in your website's root directory.

RSS Aggregators: RSS Aggregators is client software that uses web feed to get back syndicated web content such as blogs, podcasts, vlogs, and mainstream mass media websites.

Redirect: Redirect refers the process of mechanically sending a site visitor to another Internet location. The locality can be a subdirectory on another site or even an exacting web page.

Return Visitor: Return visitor refers a visitor who can be recognized with multiple visits, either throughout cookies or authentication.

ROI: Return On Investment: - Return On Investment relative to search engine advertising which is regularly refers to sales per lead and its is a calculation of how much return you get from each marketing dollar.

Rewrite: This technique also known as URL rewriting

Ranking: Ranking is known as your position in the search results that present when someone searches for an exacting keyword at a search engine.

Referrer: Referrer is a webpage from which a user or a viewer has come.

Registration: Registration is known as a company or a website which permits you to register domain names or URL or the procedure of submitting your website into a search engine or directory in order for it to be indexed.

Relevancy: Relevancy is basically a calculation of how useful searchers locate search results and likelihood which web page will be of importance or useful to a search engine viewer for a keyword search..