"If I'm getting paid by a client, I don't blog about it. That's my personal set of standards," Armstrong said. "I'm not going to hold anybody else to my personal standards. I'm not going to make that universal."

The growing influence of blogs such as his is raising questions about whether they are becoming a new form of journalism and in need of more formal ethical guidelines or codes of conduct.

According to the Pew Internet and American Life Project, 27 percent of adults who go online in the United States read blogs. And blogs have greater impact because their readers tend to be policy makers and other influencers of public opinion, media experts say.

So far, many bloggers resist any notion of ethical standards, saying individuals ought to decide what's right for them.

Blogging is more like a conversation, and "you can't develop a code of ethics for conversations," said David Weinberger, a prominent blogger and research fellow at Harvard's Berkman Center for Internet and Society.

Others, however, have pushed written guidelines.

Jonathan Dube, managing producer at MSNBC.com and publisher of CyberJournalist.net, modified the Society of Professional Journalists' code of ethics and urged fellow bloggers to adopt it. The principles: Be honest and fair. Minimize harm. Be accountable.

Longtime blogger Rebecca Blood circulated guidelines that call for disclosing any conflicts of interest, publicly correcting any misinformation and linking to any source materials referenced in postings.

"It seems pretty clear to me that having some kind of standard contributes to an individual blogger's own credibility," she said.

Yet Blood knows of fewer than 10 bloggers who have adopted her guidelines by linking to the document.

How bloggers handle matters of ethics and disclosure vary greatly.

While Armstrong suspended his blog, a partner in his political consulting firm, Markos Moulitsas Zuniga, kept his going and instead posted a disclosure about the payment. The Dean campaign had paid the pair $3,000 a month for technical consulting services.

Others saw no need to disclose at all. In South Dakota, blogger Jon Lauck said many knew that he was a paid consultant to John Thune's Senate campaign, but Lauck didn't believe he had to post any "flashing banner" on his site.

Many news organizations have formal guidelines separating editorial and business operations, and journalism schools and professional societies try to teach good practices.

Bloggers, though, tend to shudder at being called journalists, even as lines between the two blur.