Email Marketing
The first email, sent by Ray Tomlinson in 1971 or 1978 depending on your sources, marked the beginning of the modern communications and the messages was nothing to special, of numbers and letters that looked more like a password than a messages, but its significance was profound. The email was sent from one computer to another, traveling through a networks of machine, not unlike the internet we know today. Tomlinson introduced the "@" symbol in email address to the world.
Gary Thuerk, a Marketing Manager at Digital Equipment Corporation sent the first commercial email years later, where the message reached a list of email addresses. And voila, email marketing was born. There were only a few hundred peoples on the list, but that was enough for to claim the mantle, "Father of Spam."