FORTUNE’s current cover story includes a big piece on blogs, Why There's No Escaping the Blog, which I wrote with my colleague Dan Roth. The main point of the story: Blogs are not only a new form of publishing, but also a new form of communication. Blogs are comparable in import to e-mail or instant messaging. As a result, they will have a huge impact on business.

With blogs, ordinary people, for the first time, can easily create and manage their own websites. That’s not the only reason they are catching on, though. These online personal journals are structured fundamentally differently from the web as we’ve known it up until now. Blogs are not built around the fundamental building block of the rest of the web—the page. Instead, blogs are built around the post—a piece of content created at a specific time. Each post has a unique, permanent web address called a permalink. Bloggers routinely link to one another’s posts, which remain accessible indefinitely. That linking gives blogs a viral quality, so an intriguing post can get broad attention amazingly fast.

Magazine stories are published under tight space constraints, so there was lots of great stuff Dan and I had to leave out of our cover story. For instance, there’s much more to say about the impact of blogs on advertising and public relations. Starcom MediaVest Group, one of the world’s largest media-buying companies, has set up a new unit, called Reverb, solely focused on informal media, including blogs. "Control of the marketing conversation has been shifting to consumers," says Dan Buczaczer, who runs Reverb. "We want to learn about and ultimately harness the power of word-of-mouth."

Buczaczer calls blogs "the killer app for citizen-generated media." He thinks the structure of blogs makes them an efficient way to measure and influence opinion. "Word of mouth relies on the influentials," he says. "It’s the tipping point. Who are the most trusted folks out there? The link system within blogs becomes a natural way for influentials to rise to the top in a way that’s easily identifiable. During the elections, the same 10 blogs were quoted over and over—they became the influentials. There’s no reason that can’t happen across every category, every hobby, and every interest." But Buczaczer warns anyone eager to jump on this bandwagon: "The first step in almost every situation is listening. Only once our clients get a strong sense of what’s being said out there do we recommend they reach out to consumers and start a conversation."

Blogging further blurs the lines between PR and advertising. "Now you’ve got to pitch the bloggers, too," says Richard Edelman, CEO of Edelman Public Relations. "You can’t just pitch the conventional media." One way Edelman does this is with e-mail lists. For Nissan, his firm sends a group of 2,000 influential auto industry thinkers and writers, including many bloggers, a monthly e-mail from Nissan's CEO Carlos Ghosn. Edelman says his staffers spend a lot of time participating in online communities and blogs, "seeding conversation, but only on a permission basis." He talks about "feeding the bloggers." A staffer might, for instance, post on a blog: "We see you’re talking a lot about female beauty. Would you like to be on our e-mail list from Unilever?" Edelman maintains his own blog, partly as a vehicle to communicate to the firm’s employees, and partly, he says, "because it sends the message to our clients that they should be doing it."

But Tony Sapienza, CEO of Topaz Partners, a smaller tech-oriented PR firm in Malden, Mass., cautions against being too facile: "Many of our clients are asking how to ‘pitch’ a blog, and we’re quick to correct them. We’ve seen bloggers expose and rip apart PR pitches that would have been perfectly acceptable to a print journalist." For a new client called HeyPix!, which operates a digital photo sharing service that bloggers can in fact use, Topaz is working with blogs, such as the quite professional Photographyblog. "We’re mindful of blog etiquette," says Sapienza. "We’re not pushing a news story, but instead simply raising awareness about this new service by mentioning it within the context of the informal dialogue stream." Sapienza says some companies should definitely start blogs, but "it’s essential that the blog is not designed to market and promote, but instead to inform and encourage dialogue." These are crucial insights that all our reporting on blogs reinforced. Topaz Partners maintains its own blog, called Tech PR Gems, on Google’s Blogger service.

Blogs may present opportunities for business, but they also present potential minefields. Some unwitting workers, who've written under their own names, have been fired for what managers considered inappropriate blog posts. And brace yourself for the big sucker punch: Employees blogging anonymously. A taste of what may come can be found on an over-the-top unsigned blog ostensibly written by an employee of The Strand, a New York City bookstore. In colorful, obscene language, the blogger complains about his job, his bosses and the store's customers. And on LiveJournal.com's self-publishing service, there's a blog where 144 participants, most of whom claim to be Wal-Mart employees, rant and rave about the retailer. Many post bile-filled comments about their work conditions.

And you thought gossip around the water cooler was annoying?

Questions? Comments? E-mail them to me at dkirkpatrick@fortunemail.