In the year 20, or maybe 33, A.I.

Maybe you missed it amid the noisy merriment of the New Year, but Jan. 1 marked a birthday worth observing. Twenty years ago on New Year's Day, the Internet as we know it was born, ushering in the era of the World Wide Web -- the closest humanity may ever get to a version of J.R.R. Tolkien's mythic global fellowship: "One ring to rule them all, One ring to find them./ One ring to bring them all and in the darkness bind them." Minus the dark overtones, that's not bad at all for a thumbnail description of the contemporary Internet in practice.

Before you protest that the Internet simply has to be more than 20 years old -- who can even remember what life felt like B.I., "before the Internet"? -- let us concede that this birthday is indeed debatable. As far as some people are concerned, the network turned 33 last September, not 20 this month. As with the abortion debate, it's all a matter of defining when life begins.

Here are the facts. The seed of the idea that became the Internet actually was sown in the 1960s, when the U.S. Defense Department's Advanced Research Project Agency developed a small network known as the ARPANET, which facilitated the sharing of supercomputers among U.S. researchers. On Sept. 2, 1969, two computers at the University of California at Los Angeles, linked by a 5-meter cable, sent data back and forth, the first fragile node of the net or web to come. Strictly speaking, that electric moment marked the true birth of the Internet.