Though many companies have Internet guidelines that prohibit visiting porn sites or forwarding racist jokes, few of the policies directly cover blogs, or Web journals, particularly those written outside of work hours.

"There needs to be a dialogue going on between employers and employees," said Heather Armstrong, a Web designer fired for commenting on her blog about goings-on at work. "There's this power of personal publishing, and there needs to be rules about what you can or cannot say about the workplace."

On blogs, which are by their very nature public forums, people often muse about their likes and dislikes — of family, of friends, of co-workers.

Currently, some 27 percent of online U.S. adults read blogs, and 7 percent pen them, according to The Pew Internet and American Life Project.

With search engines making it easy to find virtually anything anyone says in a blog these days, companies are taking notice — and taking action.

"Because it's less formal, you're more likely to say something that would offend your boss," said Lewis Maltby, president of the National Workrights Institute, a workers' rights group.

Armstrong, who wouldn't name the company that fired her in 2002, said some of her bosses took issue with such posts as "Comments Heard In, Around, and Consequent to the Company Christmas Party Last Evening."

In 2003, a Microsoft Corp. contractor was fired after posting photographs of computers from rival Apple Computer Inc. at a loading dock. Because Michael Hanscom had described a building in his posting, Microsoft said he had violated security, he said.

Last fall, Simonetti posted photographs of herself posing in a Delta Air Lines uniform inside a company airplane, her bra partly revealed in one. She was fired weeks later.

And in January, Jen was fired by Google over a blog that discussed life at the company, even though he said "it's all publicly available information and my personal thoughts and experiences."

Upon reflection, Jen said, he understood Google's concerns, given readers' tendencies to read between the lines and draw conclusions based on "random comments I made."

He said he hoped his case would prompt workers to "talk to their managers at length about blogging before they begin."

In 1997, blogging pioneer Cameron Barrett lost a job at a small marketing firm in Michigan after co-workers stumbled upon "experimental" short stories from his creative writing class on his site. Now, he's much more cautious, and he suspended his blog while campaigning for Wesley Clark.

Annalee Newitz, a policy analyst at the civil liberties group Electronic Frontier Foundation, said employees often "don't realize the First Amendment doesn't protect their job."

The First Amendment only restricts government control of speech. So private employers are free to fire at will in most states, as long as it's not discriminatory or in retaliation for whistle-blowing or union organizing.

A few companies actually do encourage personal, unofficial blogs and have policies defining do's and don'ts.

"There's always a risk, but you always have that risk anytime you put an employee on the phone," Forrester Research analyst Charlene Li said.