Email marketing

Email marketing is the act of sending a commercial message, typically to a group of people, using email. In its broadest sense, every email sent to a potential or current customer could be considered email marketing. It involves using email to send advertisements, request business, or solicit sales or donations. Email marketing strategies commonly seek to achieve one or more of three primary objectives, to build loyalty, trust, or brand awareness. The term usually refers to sending email messages with the purpose of enhancing a merchant's relationship with current or previous customers, encouraging customer loyalty and repeat business, acquiring new customers or convincing current customers to purchase something immediately, and sharing third-party ads.
History.
Email marketing has evolved rapidly alongside the technological growth of the 21st century. Prior to this growth, when emails were novelties to the majority of customers, email marketing was not as effective. In 1978, Gary Thuerk of Digital Equipment Corporation (DEC) sent out the first mass email to approximately 400 potential clients via the Advanced Research Projects Agency Network (ARPANET). He claims that this resulted in $13 million worth of sales in DEC products, and highlighted the potential of marketing through mass emails.
However, as email marketing developed as an effective means of direct communication, in the 1990s, users increasingly began referring to it as "spam", and began blocking out content from emails with filters and blocking programs. In order to effectively communicate a message through email, marketers had to develop a way of pushing content through to the end user, without being cut out by automatic filters and spam removing software.
Historically, it has been difficult to measure the effectiveness of marketing campaigns because target markets cannot be adequately defined. Email marketing carries the benefit of allowing marketers to identify returns on investment and measure and improve efficiency. Email marketing allows marketers to see feedback from users in real time, and to monitor how effective their campaign is in achieving market penetration, revealing a communication channel's scope. At the same time, however, it also means that the more personal nature of certain advertising methods, such as television advertisements, cannot be captured.
Types.
Email marketing can be carried out through different types of emails:
Transactional emails.
Transactional emails are usually triggered based on a customer's action with a company. To be qualified as transactional or relationship messages, these communications' primary purpose must be "to facilitate, complete, or confirm a commercial transaction that the recipient has previously agreed to enter into with the sender" along with a few other narrow definitions of transactional messaging. Triggered transactional messages include dropped basket messages, password reset emails, purchase or order confirmation emails, order status emails, reorder emails, and email receipts.
The primary purpose of a transactional email is to convey information regarding the action that triggered it. But, due to their high open rates (51.3% compared to 36.6% for email newsletters), transactional emails are an opportunity to introduce or extend the email relationship with customers or subscribers; to anticipate and answer questions; or to cross-sell or up-sell products or services.
Many email newsletter software vendors offer transactional email support, which gives companies the ability to include promotional messages within the body of transactional emails. There are also software vendors that offer specialized transactional email marketing services, which include providing targeted and personalized transactional email messages and running specific marketing campaigns (such as customer referral programs). 
Direct emails.
Direct email involves sending an email solely to communicate a promotional message (for example, a special offer or a product catalog). Companies usually collect a list of customer or prospect email addresses to send direct promotional messages to, or they rent a list of email addresses from service companies. 
Comparison to traditional mail.
There are both advantages and disadvantages to using email marketing in comparison to traditional advertising mail.
Advantages.
Email marketing is popular with companies for several reasons:
Opt-in email advertising.
Opt-in email advertising, or permission marketing, is advertising via email whereby the recipient of the advertisement has consented to receive it.
A common example of permission marketing is a newsletter sent to an advertising firm's customers. Such newsletters inform customers of upcoming events or promotions, or new products. In this type of advertising, a company that wants to send a newsletter to their customers may ask them at the point of purchase if they would like to receive the newsletter.
With a foundation of opted-in contact information stored in their database, marketers can send out promotional materials automatically using autoresponders—known as drip marketing. They can also segment their promotions to specific market segments.
Legal requirements.
Australia.
The Australian Spam Act 2003 is enforced by the Australian Communications and Media Authority, widely known as "ACMA". The act defines the term "unsolicited electronic messages", states how unsubscribe functions must work for commercial messages, and gives other key information. Fines range with three fines of AU$110,000 being issued to Virgin Blue Airlines (2011), Tiger Airways Holdings Limited (2012) and Cellar master Wines Pty Limited (2013).
Canada.
The "Canada Anti-Spam Law" (CASL) went into effect on July 1, 2014. CASL requires an explicit or implicit opt-in from users, and the maximum fines for noncompliance are CA$1 million for individuals and $10 million for businesses.
European Union.
In 2002 the European Union (EU) introduced the Directive on Privacy and Electronic Communications. Article 13 of the Directive prohibits the use of personal email addresses for marketing purposes. The Directive establishes the opt-in regime, where unsolicited emails may be sent only with prior agreement of the recipient; this does not apply to business email addresses.
The directive has since been incorporated into the laws of member states. In the UK it is covered under the Privacy and Electronic Communications (EC Directive) Regulations 2003 and applies to all organizations that send out marketing by some form of electronic communication.
The GDPR in 2018 imposed "a number of new requirements on companies that collect, store and process personal data from EU users, which impacts email marketers" - in particular, users' right to access information held about them; and the right to have all such information deleted at their request.
United States.
The CAN-SPAM Act of 2003 was passed by Congress as a direct response to the growing number of complaints over spam emails. Congress determined that the US government was showing an increased interest in the regulation of commercial electronic mail nationally, that those who send commercial emails should not mislead recipients over the source or content of them, and that all recipients of such emails have a right to decline them. The act authorizes a US$16,000 penalty per violation for spamming each individual recipient. However, it does not ban spam emailing outright, but imposes laws on using deceptive marketing methods through headings which are "materially false or misleading". In addition there are conditions which email marketers must meet in terms of their format, their content and labeling. As a result, many commercial email marketers within the United States utilize a service or special software to ensure compliance with the act. A variety of older systems exist that do not ensure compliance with the act. To comply with the act's regulation of commercial email, services also typically require users to authenticate their return address and include a valid physical address, provide a one-click unsubscribe feature, and prohibit importing lists of purchased addresses that may not have given valid permission.
In addition to satisfying legal requirements, email service providers (ESPs) began to help customers establish and manage their own email marketing campaigns. The service providers supply email templates and general best practices, as well as methods for handling subscriptions and cancellations automatically. Some ESPs will provide insight and assistance with deliverability issues for major email providers. They also provide statistics pertaining to the number of messages received and opened, and whether the recipients clicked on any links within the messages.
The CAN-SPAM Act was updated with some new regulations including a no-fee provision for opting out, further definition of "sender", post office or private mail boxes count as a "valid physical postal address" and definition of "person". These new provisions went into effect on July 7, 2008.