E-mail : Types, Uses, and Web Mail

 

E-mail:

Electronic mail (email or e-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. Some systems also supported a form of instant messaging, where sender and receiver needed to be online simultaneously. Ray Tomlinson is credited as the inventor of networked 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.

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, typically to a mail server or a webmail interface to send or receive messages or download it.

Originally an ASCII text-only communications medium, Internet email was extended by Multipurpose Internet Mail Extensions (MIME) to carry text in other character sets and multimedia content attachments. 

 

The basic Internet message format used for email is defined by RFC 5322, with encoding of non-ASCII data and multimedia content attachments defined in RFC 2045 through RFC 2049, collectively called Multipurpose Internet Mail Extensions or MIME. The extensions in International email apply only to email.

Internet email messages consist of two sections, 'header' and 'body'. These are known as 'content'. The header is structured into fields such as From, To, CC, Subject, Date, and other information about the email. In the process of transporting email messages between systems, SMTP communicates delivery parameters and information using message header fields. The body contains the message, as unstructured text, sometimes containing a signature block at the end. The header is separated from the body by a blank line.

Common header fields for email include:

·         To: The email address(es), and optionally name(s) of the message's recipient(s). Indicates primary recipients (multiple allowed).

·          Subject: A brief summary of the topic of the message. Certain abbreviations are commonly used in the subject, including "RE:" and "FW:".

·         Cc: Carbon copy; Many email clients mark email in one's inbox differently depending on whether they are in the To: or Cc: list.

·         Bcc: Blind carbon copy; addresses are usually only specified during SMTP delivery, and not usually listed in the message header.

·         Content-Type: Information about how the message is to be displayed, usually a MIME type.

·         Precedence: commonly with values "bulk", "junk", or "list"; used to indicate automated "vacation" or "out of office" responses should not be returned for this mail, e.g. to prevent vacation notices from sent to all other subscribers of a mailing list. Sendmail uses this field to affect prioritization of queued email, with "Precedence: special-delivery" messages delivered sooner. With modern high-bandwidth networks, delivery priority is less of an issue than it was. Microsoft Exchange respects a fine-grained automatic response suppression mechanism, the X-Auto-Response-Suppress field.^[43]

·         Message-ID: Also an automatic-generated field to prevent multiple deliveries and for reference in In-Reply-To: (see below).

·         In-Reply-To: Message-ID of the message this is a reply to. Used to link related messages together. This field only applies to reply messages.

·         References: Message-ID of the message this is a reply to, and the message-id of the message the previous reply was a reply to, etc.

·         Reply-To: Address should be used to reply to the message.

·         Sender: Address of the sender acting on behalf of the author listed in the From: field (secretary, list manager, etc.).

·         Archived-At: A direct link to the archived form of an individual email message.

 

Types:

Web-based email

Many email providers have a web-based email client (e.g. AOL Mail, Gmail, Outlook.com and Yahoo! Mail). This allows users to log into the email account by using any compatible web browser to send and receive their email. Mail is typically not downloaded to the web client, so can't be read without a current Internet connection.

POP3 email servers

The Post Office Protocol 3 (POP3) is a mail access protocol used by a client application to read messages from the mail server. Received messages are often deleted from the server. POP supports simple download-and-delete requirements for access to remote mailboxes (termed maildrop in the POP RFC's). POP3 allows you to download email messages on your local computer and read them even when you are offline.

IMAP email servers

The Internet Message Access Protocol (IMAP) provides features to manage a mailbox from multiple devices. IMAP shows the headers of messages, the sender and the subject and the device needs to request to download specific messages. Usually, the mail is left in folders in the mail server.

MAPI email servers

Messaging Application Programming Interface (MAPI) is used by Microsoft Outlook to communicate to Microsoft Exchange Server - and to a range of other email server products such as Axigen Mail Server, Kerio Connect, Scalix, Zimbra, HP OpenMail, IBM Lotus Notes, Zarafa, and Bynari where vendors have added MAPI support to allow their products to be accessed directly via Outlook.

Uses:

Business and organizational use

Email has been widely accepted by businesses, governments and non-governmental organizations in the developed world, and it is one of the key parts of an 'e-revolution' in workplace communication. It has some key benefits to business and other organizations, including facilitating logistics, helping with synchronization, reducing cost, Increasing speed, possibility of auto-processing and improved distribution, Email marketing.

Personal use

Many users access their personal emails from friends and family members using a personal computer in their house or apartment. Mobile "apps" for email increase accessibility to the medium for users who are out of their homes. Individuals often check emails on smartphones for both personal and work-related messages.

Email attachment:

Email messages may have one or more attachments, which are additional files that are appended to the email. Typical attachments include Microsoft Word documents, PDF documents, and scanned images of paper documents. In principle, there is no technical restriction on the size or number of attachments. However, in practice, email clients, servers, and Internet service providers implement various limitations on the size of files, or complete email - typically to 25MB or less. Furthermore, due to technical reasons, attachment sizes as seen by these transport systems can differ from what the user sees, which can be confusing to senders when trying to assess whether they can safely send a file by email. Where larger files need to be shared, various file hosting services are available and commonly used.

 

Web mail:

 

Webmail (or web-based email) is an email service that can be accessed using a standard web browser. It contrasts with email service accessible through specialised email client software.

Examples of webmail providers are AOL Mail, Gmail, GMX Mail, 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.

Webmail access is made possible through webmail software, such as Roundcube or SquirrelMail, installed and running on the email server.

As with any web application, webmail's main advantage over the use of a desktop email client is the ability to send and receive email anywhere from a web browser. Its main disadvantage is the need to be connected to the Internet while using it.

 

The first Web Mail implementation was developed at CERN in 1993 by Phillip Hallam-Baker as a test of the HTTP protocol stack, but was not developed further. In the next two years, however, several people produced working webmail applications.