The 30-year-old software analyst from Brooksville, Florida, went on to praise the inspirational message of the Fox Faith film, which would be opening that weekend, about a trust-fund baby who discovers the joy of giving. Caldwell noted that the film’s producers were letting opening-weekend ticket buyers direct a dollar from the admission to the charity of their choice.

One thing Caldwell didn’t mention: She was paid $12 to help build a buzz around the movie opening and charitable campaign — bringing her blogging-for-dollars take to more than $7,700.

Thousands of bloggers are writing sponsored posts about subjects as diverse as diamonds, digital cameras and drug clinics. The bloggers are spurred by new marketing middlemen such as PayPerPost Inc, which connect advertisers with mom-and-pop Web masters. Their irate blogging counterparts say the cottage industry is polluting the blog world and misleading consumers by blurring the line between advertising and unbiased opinion. “

The problem is the advertisers are trying to buy a blogger’s voice, and once they’ve bought it, they own it,” said Jeff Jarvis, a City University of New York journalism professor who writes about technology at BuzzMachine.com.

“PayPerPost versus authentic blogging is like comparing prostitution with making love to someone you care for deeply. No one with any level of ethics would get involved with these clowns,” said Jason McCabe Calacanis, an entrepreneur who co-founded Weblogs Inc, a network of blogs that includes Engadget. The bloggers who take assignments from the likes of PayPerPost, ReviewMe, SponsoredReviews.com and Loud Launch call the hubbub overblown. They say the services provide a way to make a profit or keep their blogs going. Technorati, a search engine that tracks 71 million blogs, says 175,000 new ones are created daily.

Posties, as PayPerPost calls its crew of 15,500 bloggers, say their posts are sincere, sponsored or not, and that financial incentives are disclosed. “I would never make up a lie,” Caldwell said. “My sister reads my blog, and she would call me out.”

-Josh Friedman