SEO glossary entries for ‘R’

RankBrain: See ‘RankBrain algorithm’
RankBrain algorithm: Is a set of logical rules, derived by Artificial Intelligence (AI), to interpret the meaning of users’s search expressions, so that it can return pages that match their semantic intent, but might not contain the exact words that were searched for. The application of AI suggests that it is considerably more sophisticated than a mere synonym dictionary; taking into account all sorts of context defining factors for the searcher and the extression. It is considered to be the third most powerful ranking factor after words and links.
Really Simple Syndication: See ‘RSS’.
Reciprocal Links: Links provided by two or more sites to each other, conditional on the original target site providing links back to the original link providing site.
Referring Keyword: A user search term which results in a click-through to a given website.
Relevancy: May have a distinct American meaning, but it looks like mistaken use of the term ‘Relevance’. See ‘Relevance’.
Repeat Traffic: Repeat traffic is a web metric which measures the number or proportion of visitors who return to the same page or site at least once.
ROI: See ‘Return on Investment’.
Root Directory: A Root Directory is the folder (or directory) on a computer filesystem that contains all the other folders (directories) and files. In SEO, the same term typically refers to the folder (or directory) on a web server's filesystem that contains all the other folders (directories) and files associated with a single website. Since one webserver can host many websites, it is quite normal for a single webserver to have many root directories in the SEO sense. However, no individual website can ever have more than one root directory, in the SEO sense.
Root Domain: The concept of a root domain is neither clearly defined nor consistently deployed in most SEO. More often than not, SEO specialists use the term to distinguish domain names that are closer than others to what the ‘Domain Name System’ (DNS) would consider to be a ‘Root Zone’. For example, a domain name like example.com is typically referred to as a Root Domain in SEO, even though it is, strictly speaking, a sub-domain of the top level com domain. In other words, because no individual site can serve web pages from the DNS top-level domains, SEO specialists (and presumably, search engines) consider immediate sub-domains of top-level domains as Root Domains. While domains like www.example.com are treated as sub-domains. National domains, such as .uk and .au have, however, been treated differently in the past. Since no individual site could own the immediate sub-domains of .uk, it's sub-sub-domains (e.g. example.co.uk or example.gov.uk) were treated as Root Domains by SEO specialists. It is not yet clear whether the recent decision to sell immediate sub-domains (such as example.uk) will result in domains like example.co.uk being down-graded. That seems quite unlikely, despite what domain name registrars would have you believe. Not least, because it would completely undermine the traditional policy of privileging sites which have served top quality content from the same domain for many years. The higher price of many new ‘Top Level Domain Names’ (TLDs) might distinguish deep-pocketed multi-nationals from the minnows, but it's not at all clear how that metric would help Google distinguish good quality content from bad.
RSS: Stands for ‘Really Simple Syndication’, an XML format designed for sharing headlines and snippets of web content. Typically, an RSS newsreader or RSS aggregator is used to subscribe to syndicated feeds of content from Blogs and news sites. Since RSS is the primary means of distributing blog content, it clearly plays a significant role in the ‘content marketing’ dimension of SEO. Since the name itself points to some of the technical limitations of RSS, many blogs will deliberately favor the ‘Atom’ protocol for distributing content in much the same way as RSS.
RSS reader: An RSS reader is a ‘news aggregator’.
Running Text: See also ‘Default Running Text’.