Raymond Tomlinson was just horsing around, basically, when he thought it might be interesting to send a file across a network. He chose the "@" symbol because it just "made sense" - a user, at some computer. He was working for the Department of Defense, as a tech, but did this on his own time - with no idea that he was about to change the world. The acknowledged first "killer app" of the internet was born. I wonder how he answers when he's doing business and people ask, "Do you have an email where you can be contacted....?". Must be fun to say, 'Heck - I INVENTED email - honest!".