Electronic mail

Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Invented by Ray Tomlinson, email first entered limited use in the 1960s and by the mid-1970s had taken the form now recognized as email. Email operates across computer networks, primarily the Internet. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need to connect only briefly, typically to a mail server or a webmail interface, to send or receive messages.

History

The history of email is shrouded in the development of the Internet, ARPANET, and computer networking. The concept of sending electronic text messages between parties, similar to mailing letters or memos, predates the creation of the Internet. Early email systems required the author and the recipient to both be online at the same time, in the same way that instant messaging systems do today. This limitation was removed in the early 1970s when Ray Tomlinson sent the first email between two machines on the ARPANET, marking the invention of the email system we know today.

Functionality

Email operates on a simple model: A sender composes a message using a mail user agent (MUA) and sends it to the recipient. The message is then relayed through a series of mail transfer agents (MTAs) to the recipient's mail server. The recipient's MUA then downloads the message from the server. Today, email is used for both personal and professional communication, supporting attachments that allow users to share documents, images, and other files.

Components

- Mail User Agent (MUA): Also known as an email client, it allows users to send and receive email. Examples include Microsoft Outlook, Mozilla Thunderbird, and web-based clients like Gmail. - Mail Transfer Agent (MTA): A software that transfers email from the sender's to the recipient's server. Examples include Sendmail and Postfix. - Mail Delivery Agent (MDA): Software that delivers email to the recipient's mailbox. - Mail Access Protocol: Protocols such as IMAP and POP3 that retrieve email from a server. IMAP synchronizes the email on the server with the user's client, whereas POP3 downloads the email to the user's device.

Security and Privacy

Email security is crucial, as email is often targeted by phishing, spam, and malware attacks. Techniques to improve email security include the use of encryption (such as PGP), two-factor authentication, and careful scrutiny of email attachments and links. Privacy concerns also arise with email, particularly in relation to the storage and interception of emails by third parties.

Regulation and Standards

Email is governed by a series of Internet standards developed by the Internet Engineering Task Force (IETF). These include standards for email formats (RFC 5322), transmission (SMTP), and access protocols (IMAP/POP3).

Future of Email

Despite predictions of its decline, email remains a fundamental part of personal and professional communication. Innovations such as email encryption, machine learning for spam detection, and integration with other communication tools suggest that email will continue to evolve. Template:Communication-stub