The East Bay Express - an alternative SF Bay area publication - today published a piece about Google's advertising filters and the impact they have - and potentially have - on independent news coverage. It's an interesting read. From it:

Earlier this year, Salon signed a small advertising contract with Google, and employees quickly discovered that whenever a story dealt with sex too explicitly, the search engine would automatically pull its ads. Salon ran stories about a Senate hearing on the effects of pornography, a study on the effect of sex on stress levels, and British attitudes toward rape victims; Google pulled its ads for each of these articles. "What we found in working with Google was that because some of our content violated its 'family-safe policy,' as a result we had to work with other partners such as Yahoo," says Kathryn Surso, Salon's vice president of business development....

...Few bloggers rely on ad revenue to pay their bills, and Salon's advertising base is sufficiently diversified that dropping the occasional Google ad doesn't hurt it. But for smaller Web news outfits, losing Google revenue is much more serious. According to the publisher of a prominent news Web site who agreed to speak only if granted anonymity, his company recently signed a premium Google advertising contract that now accounts for a third of his site's revenue. A few months ago, his Web site ran a series of stories about a major bombing in Iraq. Within hours, he says, Google's ads vanished from his home page, and so did all the revenue they generated. "They said we had the word 'kill' on our site, and that killed the ads," the publisher said. "I wrote them and said that would be very difficult for a news site, which would often use the word 'kill.' They said, 'Those are the rules.'"

...When the publisher contacted Google and asked for explicit guidelines about what constitutes illicit content, company representatives refused. "I asked them for a set of keywords, and they wouldn't give me one," he says. "I don't know what the words are; we just have to approach it by toning down the language in our articles. ... It's just ridiculous. I don't think the [advertisers] are going to have a problem with us reporting the news. ... But they're Google, and we're a small site. So we'll have to conform to their regulations if we want their money."