Due to the massive growth of the Internet, most countries have passed legislation to prevent companies from sending unsolicited emails. These laws determine what is and what is not considered acceptable email correspondence, and enforce restrictions on email communications. In the United States and Europe, for example, bulk email must contain an accurate from field and subject line, and the email content must include the sender’s physical address. In addition, a blast email must also offer its recipients the opportunity to unsubscribe from the email list — and such requests must be met within a specified period of time. As a result of these laws, it is very important for companies to maintain an updated list of subscriptions and cancellations at all times, and avoid sending out email that appears to be spam.
Digital marketing is also referred to as 'online marketing', 'internet marketing' or 'web marketing'. The term digital marketing has grown in popularity over time. In the USA online marketing is still a popular term. In Italy, digital marketing is referred to as web marketing. Worldwide digital marketing has become the most common term, especially after the year 2013.
Although there’s no panacea for direct mail’s attribution problem, Simpson says that he shores up his data by matching a list of recent buyers with consumers from the campaign’s direct mail list. This method is more inductive than deductive, in that he cannot be entirely sure the direct mail led to the purchase, but it allows him to have an idea of how effective a direct mail campaign has been.
The first known large-scale non-commercial spam message was sent on 18 January 1994 by an Andrews University system administrator, by cross-posting a religious message to all USENET newsgroups. In January 1994 Mark Eberra started the first email marketing company for opt in email list under the domain Insideconnect.com. He also started the Direct Email Marketing Association to help stop unwanted email and prevent spam.  
Most popular email marketing services offer functionality that strikes a recipient from a list once a certain number of emails to a specific recipient ‘bounced’ back as undeliverable. Don’t be overeager to remove a subscriber, though; there are valid reasons why an email cannot be delivered. Consider only removing such a subscriber after four or five “bounces”.
The subheadings in the email blast also need to engage the reader. Many recipients will not actually read the whole thing and instead, they will scan the newsletter. When they scan through the email blast, the subheadings will be one of the parts most likely to catch their attention. Use your subheadings as a way to organize the relevant information in the content of the email to make it easy for your readers to jump to the information that is relevant to them.
Emails triggered by milestones, like anniversaries and birthdays, are fun to get -- who doesn't like to celebrate a special occasion? The beauty of anniversary emails, in particular, is that they don't require subscribers to input any extra data, and they can work for a variety of senders. Plus, the timeframe can be modified based on the business model.
In the late 1990s online shoppers were mainly well-educated, high-earning, twenty- to forty-year-olds. By 2003 online shoppers represented a broader demographic, with an average age of forty-four years and an average annual household income of $65,000. Of these shoppers, 50 percent were female and 50 percent were college graduates. According to a 2004 report from the U.S. Department of Commerce, in 2003 searching for product/service information was the second most popular online activity after e-mailing or instant messaging and 77 percent of U.S. Internet users age fifteen and older shopped online. E-customers researched products and services that they were considering for purchase online. Their final purchases, however, may not have been made online.