R/S Ratio - The ratio of the number of web sites, which contain a Keyword or Keyphrase ("R", the supply) to the number of search engine searches for that keyword or Keyphrase ("S", the demand). Used as to identify attractive keywords for which there is a competition.

RAM - Abbreviation for Random Access Memory

Rank - The actual position of a website on a search engine results page for a certain search term or phrase. Usually refers to URL's or site's position in a search engine for a certain keyword or key-phrase.

Rankings - The simply the place or positioning for a website on search engine.

Rapid Inclusion - The indexing of web sites in search engines and directories based on a per page fee. As opposed to free submissions where indexes are updated every few weeks, rapid indexing occurs every 48-72 hours.

Rate Card - The document detailing prices for various ads placement options.

Raw Logs - The name for a server's log files.

RBSE - Abbreviation for Repository Based Software Engineering Program

RDBMS - Abbreviation for Relational Database Management System

RDF - Abbreviation for Resource Description Framework

Recall - Related to precision, this is the degree in which a search engine returns all the matching documents in a collection. There may be 100 matching documents, but a search engine may only find 80 of them. It would then list these 80 and have a recall of 80%.

Reciprocal Link - A mutual link exchange between two web sites. Also called a link swap. Search engines could penalize Websites with reciprocal links.

Rectangle Ad - The any one of the large, rectangular banner sizes suggested by the IAB.

Redirects - A method of moving visitors from one Web Page to another, using either server side or scripting language that tells the visitors and search engine to go to another Web Page automatically. Most search engines now penalize sites that use Redirects, typically by de-listing the offending site.

Referral Spam - Sending multiple requests to a website spoofing the header to make it look like real traffic is being sent to another site.

Referrer - A referrer is the URL of the page that the visitor came from when he entered a website. Referrer information can be accessed through the log file. If a visitor comes directly from a search engine listing, the query used to find the page will usually be encoded in the referrer URL, making it possible to see which keywords are bringing in visitors.

Refresh - See Meta Refresh

Registration - The process of requesting a search engine or directory to index a new Web page or Web site. Some registrations involve carefully written descriptions for paid and free directories.

Relative Link - A hyperlink that does not include an entire domain name, folder or subdirectory name and file name together in the URL, a link that is defined by its relative position to the current URL.

Relevance - The accuracy of the search results a measure of how close the documents listed in the search results are to the user’s search query.

Relevancy Algorithm - The method used by search engines and directories to match the keywords in a query with the content of the Web Pages in their index. Each search engine and directory uses a different algorithm and frequently changes this formula to improve relevancy.

Rep Firm - The ad sales partner specializing primarily in single-site sales.

Reseller Hosting - Arrangement whereby a company selling hosting to consumers uses the data center and equipment of another company.

Re-submission - Repeating the search engine registration process one or more times for the same web page or Web site. This could be suspicious for search engines because it can indicate spamming methods. Some search engines will de-list sites for re-submission. Most search engines and directories limit the number of submissions of the same page in a 24-hour period. Occasional re-submission of changed pages is usually not a problem.

Results List - Same as Results Page

Results Page - The page that is displayed search results after a search query is entered. See also SERP

Return Days - The number of days an affiliate can earn commission on a conversion (sale or lead) by a referred visitor.

RFC - Abbreviation for Request for Comments

RFI - Abbreviation for Request for Information

RFP - Abbreviation for Request for Proposal

RFQ - Abbreviation for Request for Quotation

RGB - Abbreviation for color palette Red - Green - Blue

RIA - Abbreviation for Rich Internet Applications. An applications such as Ajax and Flash that is providing a better user experience by delivering content in an on-demand web environment.

Rich Media - The media that offers an enhanced experience relative to older, mainstream formats.

RO - Language Code for Romanian

ROAD - Abbreviation for Return On Advertising Dollar

ROAS - Abbreviation for Return On Advertising Spend

Robot - A program that automatically request web pages in order to index the page content and/or to retrieve specific information. Often used to refer to a search engine spider.

Robots.txt - A file that is used to inform the search engine spider which pages on a site should not be indexed. This file sits in your site's root directory on the web server.

ROC - Abbreviation for Return on Customer The value each customer brings.

ROI - Abbreviation for Return On Investment. In the SEO practice refers to profit or revenue generated as the direct result of a search engine marketing campaign.

ROM - Abbreviation for Read Only Memory

RON - Abbreviation for Run Of Network ad buying option in which ad placements may appear on any pages on sites within an ad network.

ROS - Abbreviation for Run Of Site ad-buying option in which ad placements may appear on any pages of the target site.

RSS - Abbreviation for Rich Site Summary and/or Really Simple Syndication

RSS Feed - Abbreviation for Rich Site Summary and/or Rich Site Syndication. RSS feeds use an XML document to publish information.

RTF - Abbreviation for Rich Text Format also file extension: filename.rtf

RTFM - Abbreviation for Read The "Full" Manual, that is refer to users ability read instructions before ask the questions.

RU - Language Code for Russian

RUR - Currency Code for Russia Rubles