Recently, online publishing and advertising circles have been buzzing with debates about so-called "scumware" -- trojan-horse software programs that alter the content of Web sites as viewed through a user's browser.

A program called TOPtext by Ezula Inc. has gained a lot of attention. TOPtext usually arrives on a user's computer as an auxiliary program during installation of a primary program, such as KaZaA's file-sharing application. Once TOPtext is running, it acts as a Web browser plug-in and places a kind of browser-based overlay onto a Web site so that the user sees extra links that don't appear on the original site. These links lead to advertising. To see an example, visit http://www.scumware.com/wm2.html .

Web publishers are outraged that an application could be used to hijack their users and send them to Ezula's advertisers, with no money going to the publisher. Defenders of the practice seem to rely on two basic defenses:

1. Users download and install these programs themselves, so it's their choice.

2. These programs are legal and they provide advertisers with an effective medium for context-based advertising. This is just business.

Both of these arguments remind me of justifications I've heard for spam -- not so much in their substance as in their misrepresentation and cynicism.

"It's voluntary."

Do users really install scumware voluntarily? Critics have pointed out that in most cases, these ad-insertion programs are installed on users' computers by default. A user would have to uncheck a hard-to-find checkbox in order to avoid installation of the scumware program.

Yet the San Francisco Chronicle quotes one of Ezula's founders as saying, "We do not bring anything in front of the user without them wanting it. We're not forcing anybody to have it. The choice is the consumer's. Our ultimate goal is users will be happy."

This reminds me of the doublespeak you often hear from spammers and their apologists: Calling a list "opt-in" when it's really opt-out, or just an out-and-out spam list created with address-harvesting software. Bending the definition of "opt-in": 'Somewhere in some unnamed context, you have expressed interest in business opportunities or pets or healthcare or real estate, therefore you have "opted in" to receive promotions of this type.' Or how about this justification: 'You have an email address listed on your Web site, therefore anybody has the right to send you any email they want, and you shouldn't complain.'

"It's just business."

For many business people, the only criterion for judging a business practice is whether it makes money or not. Now to a certain extent I can understand that point of view. When I'm working with a client, I'm obligated to look out for their financial interests. However, as much as we all need to make money, the reality is that human endeavor is not principally about greed. Personal gain is not a justification for just any kind of behavior.

One of the most powerful arguments against both spam and the new scourge of scumware is that these practices rob others of their resources. Spam hijacks the computing resources of its recipients and the intervening networks. And scumware does the some thing with the content of its victims' Web sites.

Those who support unethical business practices often resort to cynical, convoluted arguments in an attempt to justify their viewpoints. No one in business would claim that competition is a bad thing. But competitiveness is not a justification for theft.