In late 1971, Ray Tomlinson was part of a group developing the TENEX time-sharing system. Back in the day, computing power was centrally located and you paid for your slice of time on the mainframe. If you were on site, you submitted jobs via directly connected terminals. If you were off-site, you used an acoustic coupler (a telephone handset plugged into a pair of rubber form-fitted cups) to dial in to the mainframe at earth shattering speeds up to 300 BPS. Crazy, right?
Anyway, Ray was fiddling with a local messaging program called SNDMSG. This web page tells the story of how Ray morphed his SNDMSG program to communicate between remote computers. One thing I found especially fascinating about this story is the origins of the at sign “@” to indicate that the message was to go to a different host. All this in Ray’s own words.
Another example of a person who changed the world for the better and didn’t make a penny.
Here’s a link to Ray’s wiki page.
And here’s a link to an NPR interview with Ray. Be sure to click on the link to the podcast towards the top of the page.