AIM stands for America Online Instant Messaging. AIM was an early leader in the competitive IM marketplace, but fell into disfavor as AOL itself became less popular. The original service was discontinued in 2017, but fans have kept it running at this web site.

An extensible cross-desktop storage service for PIM data and meta data providing concurrent read, write, and query access.  Akonadi can be manipulated with the akonadictl command: enter “akonadictl --help" in a console window to learn more.

Any provider of data storage and data processing resources residing in some "cloud" of servers one may access via the internet.

A Comma Separated Values (or .csv) file is a plain text document in which each line, or record, is divided into fields by a specific separator character, usually a comma. The .csv format dates back to the early days of computing. It is still widely used, mainly because it is conceptually so simple.

DAV stands for Distributed Authoring and Versioning, which exists in several "flavors", such as WebDAV (for creating pages on the internet), GroupDAV (for groupware, open source software authored by a group of collaborators), and CalDAV (calendar management for groups), each one of which helps connect open source clients with open source servers.

DIGEST-MD5 is an authentication technique used to set up secure communications between a client and an internet service. It gets its name from the MD5 hashing function used to encode the client's credentials. See this Wikipedia article to learn more about it.

EWS stands for Exchange Web Services,  Microsoft®'s set of proprietary protocols for exchanging personal data between internet servers and end users, or clients. Kolab provides similar functionality.

Gadu-Gadu (aka GG) is the most popular instant-messaging app in Poland.

GMX stands for Global Mail eXchange (or, in Germany, Global Message eXchange), a free advertising-supported email service. Visit either this web site or this one to learn more about it.

A Gravatar, or Globally Recognized Avatar, is a graphic image associated with a WordPress user's email address. It is usually displayed as an 80px X 80px graphic image. Since many bloggers use WordPress software, the Gravatar is widely available.

GroupWise Messenger is an instant messaging service sponsored by Micro Focus International plc, a software company located in Newbury, Berkshire, England. You can get a copy of the Messenger software from this web site.

GSSAPI stands for Generic Security Service Application Program Interface, a sort of "dictionary" for the many security protocols in use on the internet. It consists of a program library and a set of standard subroutine calls that allow an internet client to determine which particular security protocol an internet service is using, and then to encode/decode the user's credentials appropriately.

ICQ is not precisely an acronym: it's a pun meant to sound like "I Seek You". It is one of the original IM platforms, first coming online in 1996. The software is available for download here.

IMAP stands for Internet Message Access Protocol, a widely available method for managing email messages. IMAP maintains and synchronizes local and remote copies of a set of messages -- in other words, the locally stored data for an IMAP account are a mirror image of the messages on the server.

Inline OpenPGP is an encryption protocol in which PGP signatures are directly embedded in the body of the email message. This protocol is deprecated because of technical difficulties caused by the indiscriminate use of non-ASCII characters in plain-text email messages.

IRC stands for Internet Relay Chat, an IM service that has its roots in a Finnish predecessor of the World Wide Web called OuluBox (1988). IRC has been losing users steadily for many years as social media platforms like Facebook have become more popular. The largest remaining network is known as Freenode; it can be accessed via this web site.

ISDN stands for Integrated Services Data Network, the very first set of telecommunication standards that permitted the simultaneous transmission of analog voice signals and digital data signals over a switched network of copper wires (i.e. the old-style telephone system). ISDN was unavoidable in the early days of the Internet, but has lately been supplanted by more robust technologies that permit unswitched connections over networks that utilize fiber optic cables, satellites, and very high frequency microwave transmitters / receivers. It is still widely used in a few industrial applications where a direct point-to-point connection is necessary, but is on the way out in the broader consumer market.

Jabber is an instant-messaging service that relies on the XMPP protocol. The original "Jabber" web site is no longer accepting new registrations, but the XMPP protocol is in widespread use. See this web site for more information.

KDE's email management program. Provides a fully integrated environment for sending and receiving email messages from one (or more) email account(s), maintaining as many email identities as you want to have, organizing and archiving your old email messages, and managing your personal email encryption keys.

Kolab Systems AG is a corporation headquartered in Zurich, Switzerland that provides both proprietary and open source software tools to facilitate collaboration among groups of people who share data, messages, and calendaring / scheduling resources via the internet. EWS  provides similar, though wholly proprietary, software packages.

The Lightweight Directory Access Protocol (or  ldap) is a standard protocol, or method, for sharing some particular classes of information among the many server computers that comprise the internet.

An LDAP Data Interchange Format (or .ldif) file is a type of plain text file designed for exchanging directory information among the various servers in a distributed network.

"Meanwhile" is open source software designed to communicate with IBM's "Sametime" instant messaging software. See this web site if you want to learn more about it.

MIME stands for Multipurpose Internet Mail Extensions, a set of coding conventions designed to make email messages more flexible by enabling features like extended character sets, embedded images, "rich text" coding, etc. The original email coding conventions supported nothing besides plain text (or encrypted) messages written with 7-bit ASCII code. Almost all contemporary email messages are MIME encoded.

OpenPGP/MIME refers to an encryption convention for MIME encoded email messages. A special set of MIME headers are wrapped around the PGP signature, allowing an email client program to conceal the signature when the message is displayed.

Open-Xchange AG is a corporation headquartered in Cologne, Germany that provides both proprietary and open source software tools to facilitate collaboration among groups of people who share data, messages, and calendaring / scheduling resources via the internet. EWS  and Kolab provide similar software packages.

PCS stands for Personal Communication Service, which is basically a cell phone with some extra functionality built in. PCS phones operate on a higher frequency band than traditional cell phones, which implies that they can provide more bandwidth than older cell phones.

PGP stands for Pretty Good Privacy, a data-encryption program that was released by Philip Zimmerman in 1991. Most email encryption software in use today employs some variant of PGP to encrypt, decrypt, and cryptographically sign messages.

KDE's Personal Information Management system, a suite of programs to help you manage your contacts and your schedule. PIM includes Kontact,  KMail,  KAddressBook,  KOrganizer,  Akregator, and Akonadi. Also used more generally to describe any system for managing personal information such as names, addresses, telephone numbers, etc.

QR Code stands for Quick Response Code, a two-dimensional barcode used to represent digital data. It was invented in Japan in 1994 for use by automobile manufacturers, but has spread far and wide, so that it is ubiquitous today.

SASL stands for Simple Authentication and Security Layer, a framework for client authentication (passwords and usernames) and data security (encrypted connections). It supports more than a dozen different protocols.

S/MIME stands for Secure / Multipurpose Internet Mail Extensions, a standard cryptographic method for signing, encrypting, abd decrypting email messages. Unlike PGP , which uses private keys, S/MIME uses publicly published encryption keys certified by a Certificate Authority, such as Verisign.

S/MIME Opaque stands for the "opaque" version of Secure / Multipurpose Internet Mail Extensions. It is is similar to the "S/MIME" format defined above, but the entire contents of the message are rolled up into a single MIME object. (Most MIME encoded email messages consist of two or more separate MIME objects.)

SMS stands for Short Message Service, a text-messaging service built into most telephone, internet, and mobile device communication networks. It facilitates the exchange of text messages that are less than 161 bytes long.

SSL stands for Secure Socket Layer, a deprecated cryptographic protocol that has been largely supplanted by TLS.

TLS stands for Transport Layer Security, a cryptographic protocol that is widely used to secure internet communications. Its primary function is to allow a client and a server to exchange enough information securely that they can set up a pair of encryption / decryption keys for use during the rest of the internet session. TLS is the weakest link in the chain connecting a client program to a secure (encrypted) internet service. It has been the target of several hacking exploits, and it has been revised several times in response to those attacks.

The Virtual (business) Card Format (or .vcf) is a keyword-oriented data interchange format that has gone through several iterations (2.0, 2.1, 3.0, etc.) since its introduction ca. 1990. The most recent version is vCard 4.0.

XMPP stands for Extensible Messaging and Presence Protocol, the basic technological underpinning for the "Jabber" instant messaging service.