A published list of IP addresses known to be sources of spam

Email programs such as Outlook Express and Opera Mail that come bundled with a Web browser

A test that uses a word-verification graphic designed to differentiate humans from automated senders during online transactions

CAPTCHA = (Completely Automated Public Turing Test to Tell Computers and Humans Apart)

An email program that is independent of any specific Web browser, and that you can use to send email messages.

A combination of characters that, when read sideways, helps convey emotion in an email message.

An open-source version of PGP, used for encrypting and decrypting email messages, that does not use patented algorithms

A block of information attached to a piece of data. The first part of a network packet. Can contain network addressing information or additional information that helps computers and applications process data.

A unique numerical address assigned to a computer or device on a network.

An email server program that receives sent messages and delivers them to their proper destination mailbox.

A messaging component used as a stand-alone application by the user.

A messaging component that routes, delivers, and receives email.

A protocol that enables operating systems to map file name extensions to corresponding applications

A small, handheld computer used for personal information management. The predecessor to the smartphone.

A tool used to schedule appointments and meetings, store contact information, and manage tasks.

A protocol that resides on an incoming mail server.

A method of encrypting and decrypting email messages. It can also be used to encrypt a digital signature.

Slang term for the standard postal service.

Unsolicited and unwanted email messages; the equivalent of junk mail.

An email client program that identifies and filters out spam messages before they reach the email Inbox

A unique name or number that identifies you when logging on to a computer system or online service. In an email address, the part before the @ symbol.