How did the “@” symbol become part of email addresses?

Ray Tomlinson chose the @ symbol because it made logical sense: it reads as "user at host." It wasn't used in usernames, and it clearly separated the person from the system.

In his design, kraken@tidalmail.com means "kraken" is the user, and "tidalmail.com" is the mail host.

The symbol became so iconic that in 2010, the Museum of Modern Art (MoMA) in New York "acquired" it for their permanent design collection, recognizing it as one of the most elegant and transformative symbols in digital communication.

It's like marking the destination port on every cargo manifest to ensure the shipment reaches the right harbor.