Tim Berners-Lee
loreweb devnetworking
The author of the 1989 CERN proposal that became the World Wide Web, and of the first browser, server and page - and the 2016 Turing Award recipient for it.
He wrote three things that had to exist together for any of them to be useful: an addressing scheme, a transfer protocol and a markup language. The decision with the longest consequences was not technical: CERN put the specification into the public domain in 1993, and the web spread because nobody had to ask permission or pay a licence. Compare any contemporary networked hypertext system that did neither, and the difference in outcome is almost entirely that.
Also known as: berners-lee, www