A growing area of content creation in which information is represented graphically and often interactively. This can be used for subjects as diverse as an analysis of a speech by the president and the popularity of baby names over time. While it has deep roots in academia, data visualization has begun to emerge on content sites as a way to handle the masses of data that are being made public, often by government. There are many tools for data visualizations, including Seattle-based Tableau and IBM’s Many Eyes. Data visualization should 1) tell a story, 2) allow users to ask their own questions and 3) start conversations.

Data-Management Platform (DMP) is a centralized computing system for collecting, integrating and managing large sets of structured and unstructured data from disparate sources.

A piece of code containing the agreed-upon terms (negotiated pricing, for example) between an advertiser and publisher that allows the advertiser to access the publisher’s inventory

When the mind becomes fatigued after a sustained period of decision making, such as when faced with too many options on a website.

A dedicated IP (Internet Protocol) is a unique Internet address dedicated exclusively to a single hosting account.

Deferred revenue, or unearned revenue, refers to advance payments for products or services that are to be delivered in the future.

Deprecated code is code that is no longer included in the language specifications. Generally, this happens because it is replaced with more accessible or efficient alternatives. This happens when a new version of a programming language or framework is released.

Stands for Dynamic HyperText Markup Language. DHTML fuses XHTML (or any other markup language), the DOM, JavaScript (or other scripts), and CSS (or other presentation definition languages) to create interactive web content.

A web framework that is popular among news and information sites, in part due to its origin at Lawrence Journal-World in Kansas. It is written in Python, a sophisticated dynamic language. Major projects built in Django include Disqus, Everyblock.com and TheOnion.com. News applications teams, including those at the Chicago Tribune and Los Angeles Times, use the framework to present large data sets online in easily accessible ways.

Stands for ‘Domain Name Service’ or alternately ‘Domain Name System’, or ‘Domain Name Server’. The DNS converts IP addresses into domain names. DNS servers are provided with the IP address of your web server when you assign your domain name to those servers. In turn, when someone types your domain name into their web browser the DNS servers translate the domain name to the IP address and point the browser to the correct web server.

The doctype declaration specifies which version of HTML is used in a document. It has a direct effect on whether your HTML will validate or not.

An increasingly popular type of database. In contrast to relational databases, which rigidly require information to be stored in pre-defined tables, document-oriented databases are more free-flowing and flexible. This is important when you don’t know what is going to be thrown at you. Documentoriented databases retrieve information more quickly but store it less efficiently. The same document-oriented database might let you store the information for an article (headline, byline, data, content, miscellaneous) or for a photo (file, photographer, date, cutline). MongoDB is a popular open source document-oriented database.

Stands for Document Object Model. It is a language-independent, cross-platform convention for representing objects in XML, XHTML, and HTML documents. Rules for interacting with and programming the DOM are specified in the DOM API.

The domain is the name by which a website is identified. The domain is associated with an IP address. Domains can be purchased with any combination of letters, hyphens (-), and numbers (though it can’t start with a hyphen). Depending on the extension (.com, .net, .org, etc.), a domain can be anywhere up to 26 to 63 characters long.

This is a scale from 1-100 that search engines use to determine how authoritative a company’s website is, 1 being the lowest rank and 100 being the highest. The higher your domain authority the more Search Engines trust you.

Double Opt-In When someone signs up through a subscribe form, an email is immediately sent to the email address they have provided. The recipient must click on the link provided in the email to re-mail to confirm their email address.

Drip marketing is a communication strategy that sends, or "drips," a pre-written set of messages to customers or prospects over time.

A popular content management system known for a vibrant open-source community that creates diverse and robust extensions. Drupal is very powerful, but it is somewhat difficult to use for simple tasks when compared to WordPress. Drupal provides options to create a static website, a multiuser blog, an Internet forum or a community website for user-generated content. It is written in PHP and distributed under the GPL open source license. Whitehouse.gov uses Drupal.

A demand-side platform (DSP) is a system that allows buyers of digital advertising inventory to manage multiple ad exchange and data exchange accounts through one interface.

Stands for Document Type Definition. DTD is one of several SGML and XML schema languages. It provides a list of the attributes, comments, elements, entities, and notes in a document along with their relationships to each other.