Evolution of Marketing Emails’ Delivery: From Mainframe To CDP

Evolution of Marketing Emails’ Delivery Infrastructure
Alex Kachalov Alex Kachalov 04 october 2022, 10:05 112
For beginners

The Early Days of Email

Just as it happened with voice communications, the earliest attempts at electronic messaging were carried out by scientists and engineers. During the 1960-70s, many incompatible mail systems were developed for mainframes and minicomputers, each one native to its own field of application.

The Early Days of Email

Such diversity did not impose any problems until the Internet, the network of networks, came into being. However, it was not until 1983 that the first common set of rules, the Simple Mail Transfer Protocol (SMTP), was implemented and adopted by different parties. Even more time passed before the current set of protocols (SMTP, POP3, and IMAP) was finally accepted as a standard around 1995.


Funny enough, the first ever unsolicited commercial email dates back to the days when the very term “email” did not yet exist. It was sent on May 3, 1978 by a promoter of Digital Equipment Corp.’s products. The public was so mad at him that no further attempts were made for almost 20 years.

With the increasing popularity of the Internet in the 1990s, the email technology opened breathtaking possibilities for advertisers and marketers. It may now sound unbelievable, but in those good old days one could write a little “spider” app to collect emails from web pages and newsgroups, and use the list to send out adverts right from their desktop computer – this was not even considered illegal! The mailing itself, however, could be painstakingly slow.

The Need For Speed

Well-behaved businesses encountered this problem, too. While desktop applications could offer a viable delivery rate (since mail systems generally accepted mail from anywhere on the net), the performance was mediocre at best – several hundred marketing emails could take an hour to send. For faster delivery, it was necessary to set up dedicated mail servers, with software capable of transferring thousands of emails fast enough for customers to receive their special offers on time. And all that without hindering the usual flow of business email correspondence.

This is where special marketing email services first came into play. Setting up and maintaining a fast email server is costly, and for many businesses the option of outsourcing the task turned out to be a favorable solution. With dedicated SMTP relay host services available at a modest price, companies only needed to perform a very simple setup to start their effective marketing campaigns.

The Problem of SPAM

As noted above, in the early days of the Internet users’ mailboxes had no protection against unwanted emails. This became a major problem in the 90’s. While the first ever large-scale commercial spam mailing occurred only in 1994, just two years later spam was recognised as a serious problem, and soon the first blacklists emerged.

The Problem of SPAM

Later, as the volume of spam increased, many other techniques were introduced. Among the most notable are server-based Bayesian spam filtering and a "Sender Permitted From" validation system designed to prevent email spoofing (later it evolved into the Sender Policy Framework, or SPF). In 2003, the CAN-SPAM Act was signed into law by President George W. Bush, adopting the first national standard for commercial emails.

Anti spam policies George W Bush

With anti-spam policies and technologies being established, the task of setting up an email delivery system became increasingly complex, to the benefit of marketing email services which have put much effort into mastering these technologies.

Features Evolve, Services Specialize

Meanwhile, with the advancement of e-commerce, the tasks each business was facing became even more complex. While a few hours’ delay may be acceptable for a large-scale email marketing campaign, a customer making an online payment wants to receive their receipt immediately. With mass mailings, on the other hand, marketers felt the need to dive deeper into the details of customer reactions to their offers, with demand for more detailed mail log analysis, better read tracking and so on.

Features Evolve, Services Specialize

This called for further specialization of email marketing services. While some put their efforts into achieving the best delivery time and offering diverse means of communications, including SMS and instant messages, others focused on features praised by mass marketing specialists, such as in-depth behavior analysis, precise segmentation and advanced reporting. Most services were now offered as web-based applications, on a pay-per-use SaaS model.

The Perfect Combo

Modern marketers collect data from different sources, and customer data handling becomes quite a challenge for them. Customer journey scenarios, funnels and automation scripts make an entire field of knowledge in its own right. To deal with the task, customer data platforms (CDP) have emerged. CDP serves like a powerhouse for your customers’ data processing, while keeping every bit of data in place where it can be easily found. CDPs are versatile enough to support different means of client communication using external transport tools.

The Perfect Combo

While SaaS services may still be a good option for small and medium-sized companies, businesses with millions of customers will benefit from a full-featured CDP combined with a powerful delivery infrastructure.

Services like UniOne offer exceptional performance (up to millions of emails per hour) while maintaining excellent deliverability and easy integration with data management platforms. And even if your demands do not yet go beyond a simple but powerful SMTP service, you may just connect to UniOne using our SMTP API, which offers decent speed while being extremely easy to set up.

Interested to know more about how to get the best email sending experience for your CDP? Take a look at our study on CDP Institute Blog.