Electronic mail is a method of exchanging messages ("mail") between people using electronic devices. Email entered limited use in the 1960s, but users could only send to users of the same computer, and some early email systems required the author and the recipient to both be online simultaneously, similar to instant messaging. Ray Tomlinson is credited as the inventor of email; in 1971, he developed the first system able to send mail between users on different hosts across the ARPANET, using the @ sign to link the user name with a destination server. By the mid-1970s, this was the form recognized as email.
Within the Internet email system, a message transfer agent (MTA), or mail transfer agent, or mail relay is software that transfers electronic mail messages from one computer to another using SMTP. The terms mail server, mail exchanger, and MX host are also used in some contexts.
The Simple Mail Transfer Protocol (SMTP) is an internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and typically submit outgoing email to the mail server on port 587 or 465 per RFC 8314. For retrieving messages, IMAP and POP3 are standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync.
An email client, email reader or, more formally, message user agent (MUA) or mail user agent is a computer program used to access and manage a user's email.
Webmail is an email service that can be accessed using a standard web browser. It contrasts with email service accessible through a specialised email client software. Examples of webmail providers are AOL Mail, Gmail, Mailfence, Outlook.com/Hotmail.com, Yahoo! Mail and IceWarp Mail Server. Additionally, many internet service providers provide webmail as part of their internet service package. Similarly, some web hosting providers also provide webmail as a part of their hosting package.
Microsoft Outlook is a personal information manager software system from Microsoft, available as a part of the Microsoft Office suite. Though primarily an email client, Outlook also includes such functions as calendaring, task managing, contact managing, note-taking, journal logging, and web browsing.
Messaging Application Programming Interface (MAPI) is an API for Microsoft Windows which allows programs to become email-aware. While MAPI is designed to be independent of the protocol, it is usually used to communicate with Microsoft Exchange Server.
Microsoft Exchange Server is a mail server and calendaring server developed by Microsoft. It runs exclusively on Windows Server operating systems.
Microsoft Entourage is a discontinued e-mail client and personal information manager that was developed by Microsoft for Mac OS 8.5 and later. Microsoft first released Entourage in October 2000 as part of the Microsoft Office 2001 office suite; Office 98, the previous version of Microsoft Office for the classic Mac OS included Outlook Express 5. The last version was Entourage: Mac 2008, part of Microsoft Office 2008 for Mac, released on January 15, 2008. Entourage was replaced by Outlook for Macintosh in Microsoft Office for Mac 2011, released on October 26, 2010.
The following tables compare general and technical features of a number of notable email client programs.
Outlook on the web is a personal information manager web app from Microsoft. It is included in Microsoft 365, Office 365, Exchange Server 2016/2019, and Exchange Online. It includes a web-based email client, a calendar tool, a contact manager, and a task manager. It also includes add-in integration, Skype on the web, and alerts as well as unified themes that span across all the web apps. Outlook on the web is navigated using the App Launcher icon which brings down a list of web apps from which the user may choose. In 2015, Microsoft started upgrading Outlook.com and Outlook on the web to use the Office 365 infrastructure, which was almost complete in January 2017 after the next version of Outlook.com was released.
Push email is an email system that provides an always-on capability, in which new email is actively transferred (pushed) as it arrives by the mail delivery agent (MDA) to the mail user agent (MUA), also called the email client. Email clients include smartphones and, less strictly, IMAP personal computer mail applications.
An email hosting service is an Internet hosting service that operates email servers.
The following tables compare general and technical information for a number of notable webmail providers who offer a web interface in English.
Bynari is a company based in Dallas, developing server and email software, mainly known for its Insight Family, similar to Microsoft Exchange Server with Outlook.
Exchange ActiveSync is a proprietary protocol designed for the synchronization of email, contacts, calendar, tasks, and notes from a messaging server to a smartphone or other mobile devices. The protocol also provides mobile device management and policy controls. The protocol is based on XML. The mobile device communicates over HTTP or HTTPS.
A mailbox provider, mail service provider or, somewhat improperly, email service provider is a provider of email hosting. It implements email servers to send, receive, accept, and store email for other organizations or end users, on their behalf.
Nokia Mail and Nokia Chat were services developed by Microsoft Mobile and earlier by Nokia for its mobile phones. The service operated as a centralized, hosted service that acted as a proxy between the Messaging client and the user's e-mail server. The phone did not connect directly to the e-mail server, but instead sent e-mail credentials to Nokia's servers. On 13 August 2008 Nokia launched a beta release of "Nokia Email service", a push e-mail service, later incorporated into Nokia Messaging. The original version of Nokia Messaging was launched in 2008 with the Nokia N97 line of smartphones and was exclusive to Finland, the United Kingdom, the Netherlands, Germany, Spain, Singapore, Australia and Venezuela before being expanded to other countries and was exclusive to Symbian handsets, Series 40 support was announced for 2009. The first public version of Nokia Messaging supports Windows Live Hotmail accounts, Yahoo! accounts, and Google accounts and was available in 12 languages.
The history of Microsoft Exchange Server begins with the first Microsoft Exchange Server product - Exchange Server 4.0 in March 1996 - and extends to the current day.
Kopano is an open-source groupware application suite originally based on Zarafa. The initial version of Kopano Core (KC) was forked from the then-current release of the Zarafa Collaboration Platform, and superseded ZCP in terms of lineage as ZCP switched to maintenance mode with patches flowing from KC. Kopano WebApp similarly descended from Zarafa WebApp. Since October 2017, Kopano Core is also known more specifically as Kopano Groupware Core, since Kopano B.V. developed more products that were not directly requiring groupware components.
