SEO glossary entries for ‘D’

Dampening Filter: A filter which Google is supposed to apply to newly discovered links, so that their value is lower than the score which the same link would be given, once it has been around for a long time. See ‘Link Dampening’.
Dayparting: Displaying adverts at specific times during a day or week.
De-indexing: Two meanings: one broad and one narrow. Broadly speaking, the process of removing all links to a given website from the search results shown to users. More narrowly, and technically, it means removing all records of the given website from the search engine's own database index. The broader meaning is probably more accurately described by the term ‘De-listing’.
De-listing: Removing all links to a given website from search results or from a ‘Web Directory’.
Dead Link: A link that produces an HTTP 404 status code, i.e. page not found.
Deep-linked Content: Content not on the homepage of web site, which has hypertext links to it. A completely redundant bit of marketing-speak, since homepages are primarily summaries or indexes of content, and don't actually house any of the substantive site content anyway. A better term for the concept might be simply be ‘Content’. Since if the content is off the homepage and doesn't have any links to it, it is not technically part of the web, or even part of the website.
Deep-linking: Linking to a page other than the target site's homepage. Not a very useful concept, since the vast majority of links fall into this category, i.e. links to actual content, rather than links to a homepage summary/index of content. Useful only as a shorthand for ‘not linking to the homepage’. Like many other popular web marketing terms, its widespread currency reflects the dominance of pre-web thinking in the marketing industry.
Degraded Content: The notion of minimally functional content which is available to users, when technical constraints prevent them accessing the most modern, all-singing all-dancing version of a web page or web form. In truth, no site should ever need to present degraded ‘content’ to users, since properly coded HTML should always be readable and actionable by any browser or standards-compliant user agent. All informational content and core functionality should be available to every class of user. Only the visual presentation, and non-essential functionality should ever be degraded.
Digital Native: Those who have grown up within, and are completely comfortable with, a digital networked world.
Digital Point Free Keyword Suggestion Tool: A now defunct service, which has ceased because it depended on two free data services that are no longer available for free, i.e. Overture Search Term Suggestion Tool and WordTracker.
Direct Traffic: Visitors who arrive at the site without having followed a link, e.g. by typing a URL, pasting a URL, or following a bookmark in their browser. It has been confirmed that Google uses data from the Chrome browser to determine the frequency and likelihood of users visiting a given website. There is almost absolute consensus among SEO specialists that sites with high direct traffic rates are considered by Google to be of higher quality than those attracting very little direct traffic.
Directory: See ‘Web Directory’
Directory backlinks: Directory backlinks are hypertext links from a web ‘Directory’ to a given site.
DMOZ: See ‘Open Directory Project’.
DNS: Abbreviation for 3 closely related things: 1. Domain Name Server 2. Domain Name Service 3. Domain Name System.
Domain Diversity: Domain diversity is used in SEO to refer to the heterogeneity of domains in SERPs. The came into wider use within the SEO community following Google's ‘Bigfoot Update’ who's principal effect appears to have been to provide a wider range of domains to SERPs. See ‘Bigfoot Update’.
Domain Name Server: An always-on software application that that automatically translates backwards and forwards between numerical Internet Protocol addresses and character-based Domain Names. This term may also refer to the computer which houses this software, of such address translation is one of its primary purposes.
Domain Name Service: The service provided by Domain Name Servers, i.e. translating backwards and forwards between numerical Internet Protocol addresses and character-based Domain Names.
Domain Name System: The hierarchical system of names and zones through which both numerical and name-based Internet addresses are managed.
Domain-Level MozRank (DmR): A SEOMoz metric which measures the popularity of a domain compared with all other domains on the web. In effect it measures the number of links to the target domain from other domains.
Doorway Pages: A Doorway page is a web page that is created solely for the purpose of spamming search engine indexes (‘Spamdexing’), by stuffing those pages with phrases which match a given set of search expressions. The key feature that distinguishes a doorway page from a generic ‘Landing Page’ is the former is always designed to move visitors onwards to a different page, whereas the latter may may have content which is of intrinsic value to the user who's expression it matches. Using Doorway pages to transparently redirect users to other pages (i.e. without the visitor noticing it) is considered to be a ‘Black Hat SEO’ technique, known as ‘Cloaking’. Synonyms: ‘Bridge Pages’, ‘Portal Pages’, ‘Jump pages’, ‘Gateway Pages’, ‘Entry Pages’
Drip feed: Creating new links slowly over a period of time, rather than suddenly creating many links all at once. This approach is less likely to arouse the suspicion of search engine algorithms. A site with few links which suddenly gets hundreds of new similar-looking incoming links might trigger mechanisms that try to filter out SEO spam.
Duplicate Content: Usually refers to textual content, especially entire pages, which are virtually identically. E.g. Two web pages whose only substantial content difference is their navigation and headings, even if they are found on different sites with substantially different metadata. When search engines identify duplicate content they typically designate one to be canonical version and ignore identical search term matches in all the other copies. If you have duplicate content, you should make every effort to flag up the most suitable canonical version. Do not leave it to the search engine software to choose.
Dwell Time: Dwell time is a web metric which measures the amount of time a user, or the average user, spends viewing a given web page. It may be used in a generic sense, or to refer to a proprietary measure used by Google. In this latter case, dwell time refers specifically to the amount of time spent on a page after arriving at that page from a Google SERP. Most SEO specialists presume that longer dwell times signal higher quality or relevance to Google, although like ‘Bounce Rates’, high dwell times alone could indicate quite the opposite, e.g. that the user considered the page relevant, but then wasted a lot of time trying and failing to find what they were looking for. Dwell time may also be referred to as “long clicks versus short clicks”.
Dynamic Page: A dynamic web page is one whose content can change in response to user inputs or interaction (where interaction could be as simple a thing as clicking a link or even hovering over it). See ‘Dynamic Web Page’.
Dynamic Web Page: A dynamic web page is a web page which is freshly generated, ‘on-the-fly’ in response to a specific user request, i.e. the page may be completely customised to one user for one particular request. The request itself will be initiated by clicking on a link or completing a form, such as a search query form. The specific content of the request will be determined by the user's previous actions on the site, including any form inputs they have submitted.