THE online world can be a scary place. Over time, an entire industry has grown up to make software that will protect children from seeing the worst the Internet has to offer.

But that effort, while well intended, may be misdirected -- or at least incomplete.

Generally, Internet filters focus on pornography: preventing accidental exposure to it by young children and blocking access for inquisitive, hormonally supercharged teenagers. On the job, pornography filters keep the workplace from resembling a locker room and help keep a company out of court fighting lawsuits claiming that it allowed a hostile work environment.

That may sound like a golden market, especially since the federal government requires schools and libraries to use the technology. Yet Internet filtering is a troubled business. Those markets are nearing saturation. (The portion of the Children's Internet Protection Act that applies to libraries was struck down in federal court last spring, in a case that will be heard by the United States Supreme Court this year.) ''It hasn't been a flourishing market,'' said Safa Rashtchy, an analyst at U.S. Bancorp Piper Jaffray.

Ah, but the industry may be overlooking another market that could be very fruitful. Internet-blocking technology might well find a broader use protecting other groups of people who have actually been harmed by what they have encountered online.

We are speaking, of course, of investors.

There's dirty, and then there's dirty. If the real object here is to filter obscenity out of our lives, what blocking program worth its algorithms would let through a description of L. Dennis Kozlowski's salary and perks? And shouldn't some mechanical brain help lead the innocent away from the temptations of ubiquitous spams about penny-stock come-ons and Nigerian bank account swindles?

Some filtering products used in the business world already block access to stock-trading sites, but their goal is to increase productivity and eliminate dawdling in the office. This year, to keep up morale, those functions could serve a more purely protective role: they could keep employees from finding out how much value their 401(k)'s and mutual funds have lost and from digging themselves ever deeper into the market's hole.

In fact, many Americans could stand to be screened off from all the seductive charms of Wall Street and its boosters, both illegitimate and legitimate. Software that can block access to hot and nasty sites can certainly block access to sites like

The programming behind Internet filters could also be turned to television; society would finally get some use out of the V-chip. Heuristic algorithms (or whatever they are called) that learn to block Pamela Anderson's breasts ought to be able to block Maria Bartiromo's eyes, which are a bigger and more hypnotic target.

Software could perform a valuable service, sussing out the telltale phrases used in pump-and-dump stock schemes. The language of a financial prospectus is every bit as formulaic and clunky as that of pornography, and the phrase ''past performance is no guarantee of future results'' ought to set off an information superhighway roadblock.

As an alternative to a total restriction of access, the proscribed phrases could prompt a pop-up window that fell back on the tried-and-true tools of ridicule and humiliation: ''If you're even thinking of buying this stock, genius, why not just burn the money instead? At least then it will keep you warm for a while.''

These technological advances, if applied judiciously, might keep the next generation from inheriting only penury. And that's what protecting the children, ultimately, is about.

Drawing (Daniel Vasconcellos)