November 2001

A Smarter Web

Continued from page 3

By Mark Frauenfelder

Too Much, Too Late?

Miller believes the seamless flow and integration of information resulting from these moves will make it possible to process knowledge in a way "that solves problems, brings people closer and spurs on new ideas that never could happen before." Others, though, are not so optimistic about the Semantic Web. "It's rather ambitious," says R. V. Guha, who led development of the Web consortium's Resource Description Framework efforts in the late 1990s. (This framework is an essential tool for describing and sharing metadata.) "It would be nice if such things existed," he says, "but there are some really hard research problems that need to be solved first."

One issue concerns inference. The time it takes a computer to draw new conclusions from data, metadata and ontologies on the Web increases rapidly as rules are added to a system. Inference falls into the same category as the classic "traveling-salesman problem" of planning the shortest route through a number of cities. It's not hard to figure out the best of all possible routes when you're dealing with just a very few locations. But when you get up to only 15 cities, there are more than 43 billion possible routes. The same kind of runaway situation exists for inference, where brute-force searches for answers could lead to time-wasting paradoxes or contradictions.

And even if Berners-Lee and his cohorts meet the technical challenges, that won't be enough for the Semantic Web to click into place. There is a big question as to whether people will think the benefits are worth the extra effort of adding metadata to their content in the first place. One reason the Web became so wildly successful, after all, was its sublime ease of creation.

"The Web today is the simplest, most primitive form of hypertext," says former Sun Microsystems Distinguished Engineer Jakob Nielsen, cofounder of the Nielsen Norman Group, a Web design firm in Fremont, CA. "And that's why it was so easy to implement; that's why everybody couldstart putting up their own Web pages; that's why the Web is so big." However, while most people may be comfortable doing simplistic editing, such as marking a text as "bold," Nielsen points out, "They cannot do semantic editing, where they say, This is the author's name,' or This is the name of people I'm quoting.'"

Of course, such pessimism may be ignoring recent history. Not so long ago, the notion of millions of people learning to write HTML code seemed far-fetched-yet that's exactly what happened. Still, the hurdle of creating a Semantic Web will be higher. People can use HTML any way they want. They commonly use tables for nontabular purposes, for instance, and slap on the "subhead" tag merely to apply boldface. These kluges and shortcuts usually have only cosmetic consequences. But the same type of fudging-say, by employing "bibliography" tags to list a DVD collection-could make a page's metadata unusable.

The fact that metadata wasn't implemented right from the Web's start could also make it harder for the Semantic Web to gain acceptance. One particularly tough skeptic is Peter Merholz, cofounder of Adaptive Path, a San Francisco-based user experience consultancy. "This stuff has to be baked in from the beginning," says Merholz, who calls the Semantic Web "an interesting academic pursuit" with little bearing on society. "The Semantic Web is getting a lot of hype simply because Tim Berners-Lee-the inventor of the World Wide Web-is so interested in it," he says. "If it were just some schmuck at some university in Indiana, nobody would care."