A | B-C | D-E | F-G | H-I | J-K | L-M | N-O | P-Q | R-S | T-W | X-Z

Database
A collection of information stored in a computer which can be readily accessed when needed.

Dead Link
A hyperlink pointing to a non-existent URL.

Deep Crawl
Usually once a month, Googlebot crawls all the links it has stored in its database. This is known as the Deep Crawl.

Demographics
Statistics about customers that refer to external life patterns - such as age, sex, income level, education, size of family, etc.

Description Meta Tag
Special HTML tag in the Head of an HTML document. Contains a brief description of the content found on the page.

Direct Mail Marketing
Involves the promotion of products and services using physical brochures and information sent by mail to a target market of customers.

Directory
Usually human edited, a directory contains sites that are sorted by categories.

DMCA (Digital Millennium Copyright Act)
A declaration that protects digital works found online.

DMOZ
Also known as the Open Directory Project.

DNS (Domain Name System)
A protocol that lets computers recognize each other through an IP Address, whereas the human sees a website URL.

Doorway Page
Any page created for the sole purpose of driving website traffic from the search engines and not a functional part of the website.

Download Speed
The number of seconds required to access a file via a particular connection, i.e. dialup, broadband, etc.

Downtime
Refers to a period of time or a percentage of a timespan that a machine or system (usually a computer server) is offline or not functioning.

Dynamic Site
A site that uses a database to store content and is delivered based on the variable passed to the page.

Email Marketing
Promotion of products and services to customers via email.

EPC (Earnings Per Click)
How much profit is made with each click from a paid ad.

EPV (Earnings Per Visitor)
Total costs versus profits from total number of site visitors.

Error
Error status.

Error Page
Sometimes referred to as a 404 page.

Ethical SEO
The opposite of Black Hat SEO, or techniques which do not endanger your website and methods in harmony with search engine guidelines.

Everflux
A term associated with the constant updating of the Google algorithm between major updates.

External Link
A link that points to another website.