Michael Marx loves Barq's root beer. He frequently wears a Barq's T-shirt. He brings Barq's root beer to parties.
So it should come as no surprise that Mr. Marx, 34, of Gilbert, Ariz., keeps a blog dedicated to Barq's.
"I've been drinking Barq's for 15 years. It's my beer," said Mr. Marx, who started his blog, thebarqsman.com, last year to collect news about Barq's, commercials he likes for the drink and musings on why he thinks Barq's is the best.
As the number of blogs has grown, more consumers like Mr. Marx are keeping Web diaries dedicated exclusively to their favorite brands. Most of them are written without the consent of the companies that own the brands; a spokesman for Coca-Cola, which owns Barq's, had not heard of Mr. Marx's blog.
But some companies are starting to pay attention to blogs, using them as a kind of informal network of consumer opinion.
"In addition to viewing blogs as another media channel, it allows us to keep our pulse on the marketplace," said Ken Ross, a vice president of Netflix, the movie rental company based in Los Gatos, Calif. One of the best-known blogs about Netflix, hackingnetflix.com, was started last November by Mike Kaltschnee, who lives in Danbury, Conn.
"I post anything I find interesting, and it turns out 100,000 people a month find it interesting, too," said Mr. Kaltschnee. He also started a blog about Trader Joe's, the specialty grocery chain based in Monrovia, Calif., at trackingtraderjoes.com/.
When it comes to Netflix service, postings about scratched discs or torn return envelopes generate dozens of comments from readers. "It's sort of like the unadulterated truth about Netflix," Mr. Kaltschnee said. "We hope that Netflix reads these things and notices trends and fixes them."
For these bloggers, intertwining their personal stories and commentaries gives them a stake in defining the brand's image while linking them with fans of similar mind across the country.
"They feel like they own the brand, that it's theirs," Jackie Huba, author of the book "Creating Customer Evangelists," said of the bloggers. "They feel they're doing the world a service," she said.
For readers, these blogs, like the customer reviews on Amazon.com, help them make decisions about what to buy. And according to a survey released this spring by Yankelovich, a marketing firm based in Chapel Hill, N.C., a third of all consumers would prefer to receive product information from friends and specialists rather than from advertising.
The brand blogs also give consumers information that companies do not necessarily publicize on their Web sites. A blog about the Walt Disney Company, by John Frost of Orlando, Fla., thedisneyblog.typepad.com, attracts readers searching for information like the weather at a company theme park or the number of accidents there.
Darren Rovell, of Bristol, Conn., whose blog, firstinthirst.typepad.com, focuses on the sports drink Gatorade, said that people who typed "is Gatorade unhealthy?" into a search engine often landed at his blog. It carries both positive and negative articles about the drink, culled from the Internet, and his own commentary.
"I'm certainly not driving Gatorade's agenda," Mr. Rovell said. But after publishing the book "First in Thirst: How Gatorade Turned the Science of Sweat into a Cultural Phenomenon," Mr. Rovell has become something of an unofficial company historian for Gatorade, which is owned by PepsiCo.
Jim Romenesko, who runs a well-known Web site about the media, maintains a separate blog about Starbucks, starbucksgossip.typepad.com. He said most of his 3,000 to 5,000 daily visitors found his blog through a Google search for Starbucks.
The blog's readers are a combination of Starbucks fans, detractors and employees. They use the site as a lively forum to discuss issues like whether Manhattan should have a store on each block, the joys of Starbucks drive-through locations, and the good and bad habits of Starbucks customers and workers. When Mr. Romenesko, of Evanston, Ill., wondered why so many of the stores were offering free samples of a green tea drink, his readers filled him in on a company-sponsored competition for trips to Japan.
Steve Rubel, of New York, whose blog Micro Persuasion, steverubel.typepad.com/micropersuasion, follows the impact of blogs on public relations, argues that companies should embrace the in-depth customer feedback the blogs offer.
"It's a 24/7 focus group that's transparent and out in the open," said Mr. Rubel, adding that "the opportunity here is for companies to find their brand ambassadors."
With this in mind, the public relations firm CooperKatz & Company of New York, where Mr. Rubel is a strategist, recently sought out two bloggers to write about the Vespa, the Italian motor scooter, for a blog the company sponsors. Neither blogger is paid, and they agreed to certain guidelines before taking the assignment.
Robert V. Kozinets, an associate professor of marketing at the Schulich School of Business at York University in Toronto, said he thought consumers would be wary of bloggers sponsored by a company. "Consumers are skeptical of things told to them by companies," Mr. Kozinets said. Most consumers are searching for unbiased opinions, a niche that blogs can fill. A testimonial from one blogger can speak directly to readers in a way advertising does not.
Mr. Marx, the Barq's devotee, said he checked out Mr. Rovell's blog about Gatorade. "Since reading his blog, I've been thinking a lot about Gatorade. So I finally went out and bought one."
