The Internet is officially over the hill.
Though it might try to hide its graying hairs, it was 40 years ago today that computer scientists at the University of California, Los Angeles, established a network connection between two computers, creating the very first node of what we now know as the Internet.
At the time, Leonard Kleinrock and his colleagues were charged with developing the Advanced Research Projects Agency Network (or ARPANET), a government-funded research project in global computer communications that eventually grew into the Internet.
On Sept. 2, 1969, Kleinrock and his team succeeded in getting two computers to exchange data over a network for the first time.
Although some celebrate the net's birthday today, others say it didn't really have life until October 29 of the same year. On that day, a message was typed by Kleinrock and sent to the second node at Stanford Research Institute. That, Kleinrock has said, "was the first breath of life the Internet ever took."
It's hardly surprising that a system so complex has a hard-to-pin-down date of birth and many say either date suffices.
"It's valid to consider either one because each involved transmission between computers," said Michael A. Banks, a technology writer and author of "On the Way to the Web: The Secret History of the Internet and Its Founders."
Since its academic beginnings, the Internet has come a long way, revolutionizing nearly every aspect of human interaction.
In honor of the occasion, here's a walk down memory lane and a look at some the Internet's most significant milestones.
October 29, 1969 – Kleinrock sends first the message between two nodes, from UCLA to Stanford. The message was supposed to be "login" but Kleinrock was only able to type "lo" before the system crashed.
1971 – Ray Tomlinson, an engineer with BBN Technologies, sent the first network e-mail, choosing the @ symbol to separate the user's name from the host computer name. Why?
"Mostly because it seemed like a neat idea," he has said.
1973 – ARPANET goes global with two international nodes, one in the U.K. and one in Norway.
1979 – CompuServe and The Source offer the first online services. Users paid an initial fee and then hourly fees to read news or financial information or read news or chat.
These services marked a "really big step" in bringing consumers – not just academics and government officials – online, Banks said. Although the users couldn't communicate with users of other networks or access information hosted on other networks, they still formed some of the first vibrant emerging online communities.
1980 – CB Simulator, the first online chat service, goes online. The service was hatched by CompuServe and was named after the Citizens' Band radio, an extremely popular radio service that let individuals communicate via radio over short distances.
"Lives were changed immediately. People stayed online longer and later, fascinated with the ability to interact with several people at once," Banks writes in his book, "On the Way to the Web." "The online world and its denizens took on a new aura of reality, and the online experience grew far more entertaining and unpredictable."