The document discusses the history and growth of the internet. It defines the internet as a network of networks that connects government, university, and private computers globally to share email, files, and other resources. Key events included the creation of ARPANET in 1969, development of TCP in 1974, and adoption of TCP/IP in 1984. The internet grew from 1000 hosts in 1984 to become the largest network in the world. Intranets are internal corporate networks using internet standards, while extranets connect a company's intranet to partners via VPN tunnels over the public internet.