Editor's Note: The World Wide Web went live 20 years ago this month, on a single computer in Geneva, Switzerland. For the anniversary the Web's inventor, Tim Berners-Lee, has written an exclusive article for Scientific American. In it he confronts various threats that could ruin the Web, and explains why preserving the basic principles that have allowed the Web to flourish is essential to preventing its destruction.

While preparing the article, Berners-Lee also spoke to Scientific American about emerging Web capabilities that could change how the online and physical worlds work. This four-part series covers some of the most intriguing, including the power of linked data, social machines, free bandwidth to the masses, and Web science.

Indeed, the Web is thriving—a recent cover story in Wired magazine to the contrary notwithstanding. Scientific American editor Mark Fischetti tackles the differences between the two magazine's treatments in his blog, "The Web is (Not) Dead."


One of the Web's huge promises is that it will help people work together. Although the Web has made it easier for groups to share information and collaborate online, it could do much more. So-called social machines could allow large numbers of people to conduct better science, even to transform democracy.

You have probably already taken part in an embryonic social machine. For example, when you fill out an online form, you may be presented with a little box that has wavy-looking words in it, and you must type the words before you can proceed. This is a social machine known as captcha. By typing the words, you and other people who are seeing the same boxes are helping computers that are digitizing printed text to figure out words they cannot determine, for various technical or syntax reasons.

Luis von Ahn has pioneered these kinds of systems and taken them further. In one variation, you are shown an image and have to type a word to identify it, such as dog, house or asparagus. If a second person somewhere unknown to you types the same word, you each get a point. People play such games—games with a purpose (GWAP)—for hours, but the exercise is helping computers identify images that the machines could not recognize on their own, building up catalogs of machine intelligence.

Online review systems are simple social machines: Which restaurant should you go to? Which exercise bike should you buy? Check the reviews and ratings people have made. The ratings don't just help consumers, however; they can alter commerce. If Schwinn gets the best ratings it may sell more bikes, and vendors with poor ratings may go out of business. If most customers of the best-selling bikes comment on how much they like having a built-in heart-rate monitor, chances are that future bikes will have them.

Much larger opportunities exist, says Berners-Lee, the Web's inventor: "The question is can we design social machines to do better science, or to improve democracy? Sometimes we've been remarkably inept, as a community, at making decisions based on science, based on reason—the assessment of the facts. We need to be better at that."

In politics, he says, "we tend to view things in very simplistic terms: the Republican model, the Democrat model—which are not very well-defined models anyway. Can we organize people to be motivated to really look at the issues—the way they really look at images in those simple games?" For starters, he proposes, social machines could analyze a debate among candidates and produce a tree-like diagram showing each person's arguments and counterarguments, to reveal where the candidates really stand, regardless of their party affiliation.
 
To read about basic principles that Berners-Lee says are needed for the Web to flourish beyond its 20th anniversary this month, see "Long Live the Web."