In some ways, Tomlinson also changed language itself. His choice of the @ symbol for email popularized a once-niche character, making it synonymous with all things internet. Arguably, he paved the way for modern social networks in the process. Twitter would be a very, very different place without the @ mentions that help you chat with other users, and numerous other services use it as an easy way to share status updates.

Tomlinson received his share of formal recognition. He's a cornerstone of the Internet Hall of Fame, and he received everything from a Webby Award to a Prince of Asturias Laureate. However, he almost doesn't need those. Much like fellow internet pioneers Tim Berners-Lee or Vint Cerf, you're encountering his legacy virtually every time you hop online. And barring a sea change in communication, it's likely that the effect of his work will be felt for decades to come.