Elizabeth Feinler
The chemist who ran ARPANET's information centre for seventeen years and whose group gave the internet .com, .edu and .gov.
Feinler, known as Jake, trained as a chemist and worked in information retrieval before joining Douglas Engelbart's group at SRI in 1972. There she took over the Network Information Center, which at the time amounted to little more than a binder of contact details. Under her it became the network's directory service, with the user registry, the HOSTS.TXT host table and the whois service.
When DNS was being designed, her group proposed carving up the namespace by kind of organisation rather than by where the machines sat — hence .com, .edu, .gov, .mil and .org. Few decisions from the 1980s get typed by more people every day. She left SRI for NASA Ames in 1989 and was inducted into the Internet Hall of Fame in 2012.