Corporate blogging can be a good way to spread the word about your company, but sure you do it right.

John Butman’s workday at Boston marketing firm BzzAgent is pretty typical. He goes to company meetings, chats with employees in the hallways and occasionally has coffee with the CEO. Butman’s job, however, is unusual in one big way: He’s an outsider who has been hired to come inside the 70-employee company and blog about what goes on there.

Butman’s work includes 90 Days of BzzAgent, a blog that followed BzzAgent’s growing pains for three months last year. Labeled as an “experiment in organizational transparency,” the blog detailed everything from employee concerns about moving into a new office to a failed client pitch that left BzzAgent founder Dave Balter pretty mad. “I’ve tried to be as honest as I possibly can,” says Butman, a professional writer who describes his job as “some weird other zone” that’s part journalism and part marketing. Now he’s writing BzzAgent’s latest blog, The Bento Box, a sort of postmodern Advent calendar that features drawings and blog postings.

Balter thinks hiring an outsider to blog was a great idea. “It’s what we envision corporate transparency will be like,” he says. “If blogging stays boring, it won’t go anywhere.”

BzzAgent is just one story in the budding annals of corporate blogging, a practice that’s gaining more participants every day. One study by Jupiter Kagan Inc. expected the number of corporate blogs to double by the end of last year. Blogs are “going to have to be a part of every company’s website,” says Debbie Weil, a Washington, DC, corporate blogging consultant and author of The Corporate Blogging Book. “It will be expected.”

Blogging can be manna from tech heaven for growing companies. It gives a company personality and is a low cost way to reach potential customers and solicit product feedback. It can dramatically improve a company’s search rankings, too. “You’ll end up getting hundreds, if not thou-sands, of [website] visitors for absolutely no cost,” says Brian Brown, a Janesville, Wisconsin, small-business blogging consultant who reviews small-business blogs on his website, PajamaMarket.com.

But the impact of blogging on corporate bottom lines is still unknown, and with companies blogging about anything and everything—from Go Daddy founder Bob Parsons’ reasons why the company pulled its IPO filing to Edelman PRCEO Richard Edelman’s story of his mother’s battle with bipolar disorder—there’s the question of how much transparency is too much. “It’s like putting the minutes of meetings [online],” Brown says. “At what point do you stop with the minutiae of information?”

There’s also the issue of credibility: Can we believe what we read on corporate blogs? Some people see the term “corporate blogging” as an oxymoron, because blogging is supposed to be an organic, stream-of-consciousness experience—a concept foreign to buttoned-up, PR-sensitive corporations. The term “synthetic transparency” has entered the blog icon in the past year to describe how corporate blogs are really just engaged in a very calculated form of marketing and PR. “[It’s] pretending to be transparent because it’s cool and it makes you look good,” Weil says. “But you’re not really being transparent.” A 2006 Jupiter Kagan survey found that the majority of companies surveyed posted blog content hoping to generate “natural” buzz about their products and services.

Weil calls BzzAgent’s The Bento Box “corporate blogging 2.0”—a creative way to use blogging as a marketing and publishing channel—but she’s also suspicious because controversy swirls around BzzAgent’s business model, which enlist volunteer agents to spread word-of-mouth buzz for the company’s clientele. And there’s also the matter of paying an outsider to blog. “Are they hiring [Butman] so they can get him to manufacture the picture of what they want people to see?” asks Weil. “I’m not sure. It’s hard for me to believe that [it] is really, truly transparent.”

Balter readily acknowledges that Butman is on the payroll, and he reiterates the company’s blog guidelines, which prohibit the disclosure of BzzAgent’s financial information and require people’s consent before they appear in the blog. The point of the experiment, Balter adds, was to do some-thing different that pushes the boundaries of corporate blogging. “It’s not a marketing piece,” he says.

Butman’s role, meanwhile, hasn’t always been easy. BzzAgent’s employees were leery of him at first, and one key senior manager demanded to stay out of his 90 Days posts but eventually relented. Blog readers have chimed in, too, and not all their comments have been favorable. “People started telling me it’s not enough of a rant,” Butman says. “It was different than what people thought a blog should be.”

As companies decide what corporate blogging should be, they’ll also have to establish legitimacy with readers. “If the boss had a bad day, they don’t expect you to write about it,” Brown says. “What [readers] do expect is to be treated with respect, which means that you don’t talk about your products in public-relations-speak.” In the no-holds-barred world of the blogosphere, many companies could learn the hard way that authenticity is everything.

Chris Penttila is a freelance journalist in the Chapel Hill, North Carolina, area.