Christine Axsmith, a software contractor for the CIA, got fired for posting about torture and the Geneva convention on her blog. The blog was on Intelink, the intelligence community's classified intranet. The article is in the Washington Post by Dana Priest and entitled "Top Secret World Loses Bogger - CIA contractor is fired when internal post crosses the line".
Somehow I am always amazed at how these bloggers seem surprised to be fired. To start with, when you accept a job with a company, you normally agree somewhere (usually in the employment contract) to keep the company business confidential. In some countries (Switzerland for one) even without a contract you can be sued for disclosing business secrets - and the qualification of "secrets" is left for the employer to decide. You do receive compensation for this. Secondly, a lot of these bloggers use their work computers, which belong to the company. And you are supposed to use these tools for company, not private, business. I think part of the problem comes from the fact that the lines between work and private life are becoming blurred. To check one's email during a vacation is work-related. But to answer private emails at work can be considered stealing time from your employer. So blogging about work at work is definitely a no-no. I don't know what the equivalent for a kiss-and-tell book on the internet would be, but if one is going to do it in real time - be prepared for the consequences.