Distribution of computer resources is key. Computers are large and expensive. Shuttle data files from one site to another - cheaper than buying computers for each site. 1990 ARPA no longer funds Internet. All over the world.
Large number are from the U.S. and Western Europe.
In the past, academic and military research. In the past, through universities and corporations. Home PCs can now access the Internet. Computers on the Internet can't memorize all of the possible host names. Each host name also has a corresponding number called the Internet Protocol Address or IP Address for short.