D

Dedicated Server
A server used by a single webmaster or email administrator. A dedicated server costs more to use as an expense as it is not shared by several users. Dedicated servers work better and are stronger than shared servers. Dedicated servers also eliminate the possibility of being blacklisted.

Deduplication
The process of removing identical entries from two or more data sets such as mailing lists.

Delivered email :
Number of emails sent minus the number of bounces and filtered messages. Always a rough estimate of the actual emails delivered from many ISPs do not need the report of bounced messages.

Delivery tracking :
The process of measuring delivery rates by format, ISP or other variables and delivery failures (bounces, invalid address, server and other errors). Also a rough estimate of the actual number.

Denial of Service Attack (DOS)
When the attacker tries to end a service email or web, by flooding the service with so much data that can block or be unable to meet the genuine applications. Distributed Denial of Service (DDoS), where the denial of service attack is a network of computers instead of a single point of attack.

Dictionary Attack
When the spammer has created its electronic mailing list by using common words and names. For example, a dictionary attack aaron@yahoo.com begin with, and continue amy@yahoo.com.

Digest :
An abbreviated version of a newsletter which replaces the long-term items with active links to the full article on a website, often with a brief summary of the contents.

DomainKeys
An application of anti-spam software developed by Yahoo and using a combination of public and private "keys" to authenticate the sender's domain and reduce the likelihood of a spammer or hacker fake the sending domain address

Double Opt-In :
Double exclusion from a list in two stages, the subscription process. The subscriber signs, and then must respond to a follow-up e-mail to opt for twice its mailing list.