Tomlinson first created the email system back in 1971 during the ARPANET days. His system allowed emails to be sent between different hosts, which back in the day was revolutionary as before that, emails could only be sent to those who use the same computer. To achieve this, Tomlinson used the “@” symbol to separate users from the machine, a symbol which is still used until today and not just for emails too.
In an interview with The Verge back in 2012, Tomlinson said that he felt that emails were a better way of leaving messages as telephones required someone to be on the other end, and that not everyone could afford answering machines. “Everyone latched onto the idea that you could leave messages on the computer. As the network grew and the growth of all that accelerated, it became a really useful tool: there were millions of people you could potentially reach.”