Leonard Kleinrock of MIT and later UCLA developed the theory of packet switching, which was to form the basis of Internet connections .
As mentioned in History of the Internet and World Wide Web (n.d.), the first computer network developed and tested by the ministry in 1969 was called ARPANET (Advanced Research Projects Agency Network). It was comprised of 4 host computers. In 1972 ARPANET went public with their technological information. E-mail was adapted for ARPANET by Ray Tomlinson of BBN in 1972. He picked the @ symbol from the available symbols on his teletype to link the username and address. The telnet protocol, enabling logging on to a remote computer, was published as a Request for Comments (RFC) in 1972. The ftp protocol, enabling file transfers between Internet sites, was published as an RFC in 1973, and from then on RFC's were available electronically to anyone who had use of the ftp protocol. .
According to Walt Howe (2002), In 1974 ARPA created a common language that would allow different networks to communicate with each other, known as transmission control protocol/internet protocol or TCP/IP. TCP (Transmission Control Protocol) and IP (Internet Protocol) are sets of rules for sending information over the Internet. They also refer to the family of protocols used to connect computers and transfer data over the network. The development of TCP/IP went through several stages throughout the years. In 1982 ARPA adopted the TCP/IP language and the Internet and as a result a connected set of networks using the TCP/IP standard emerged.
As the commands for e-mail, FTP, and telnet were standardized, it became a lot easier for non-technical people to learn to use the nets. It was not easy by today's standards by any means, but it did open up use of the Internet to many more people in universities in particular. Other departments besides the libraries, computer, physics, and engineering departments found ways to make good use of the net to communicate with colleagues around the world and to share files and resources.
