5 unspoken rules that can get you fired

(MoneyWatch) COMMENTARY I guess it's human to blab about things we shouldn't. But these days, privacy is a thing of the past. Whatever you write in an email or message, anything you say in a private or public conversation, can easily end up plastered all over the Internet.

Don't even get me started on social media sites like LinkedIn and Facebook. It's all fair game. Say or write the wrong thing and you can lose your job or destroy your career. It happens all the time.

Take the 45-minute instant message rant by Keith Block, Oracle's (ORCL) executive vice president for North America, about the company's hardware products, Oracle co-president Mark Hurd, and all sorts of other things that seemed to get under the the sales executive's skin.

10 things you should never say at work
10 things you should never do at work

The IM came out during an ongoing court case between Oracle and Hewlett-Packard (HPQ). Block had apparently been traveling for five weeks and was probably just passing the time on a flight by venting to Oracle's VP of human resources, Anje Dodson. Blowing off steam or not, Block said some things he shouldn't have, including a few about Hurd, who was CEO of HP before joining Oracle. Block wrote:

"he doesn't like to travel ... he likes to stay in the U.S. and rattle around ... lots of noise, not much results ... be a f----- global president"

"does it bug anybody else that every two weeks mark gets on a [forecast] call with all the evp directs or is it just me"

"not enough room for us both ... he should be a ceo"

And so on. You get the point.

Look, it doesn't matter how powerful or accomplished you are, or whether you're an assembly-line worker or a top executive. If you break certain unspoken rules, you can lose your job or ruin your career. Here are five such rules, most of which were broken by Block (who reportedly left Oracle yesterday.) Employees should never:

Bad-mouth the boss. You should never, ever bad-mouth the boss, or your peers, for that matter. Think people won't find out? You're wrong. Juicy stuff has a way of propagating. That's what happened to Allstate president Joe Lacher, who had some unsavory things to say about his boss, CEO Tom Wilson, at a company event last year. Two weeks later, Lacher was gone "effective immediately," according to a terse press release.

Put something in writing you wouldn't want posted on Yahoo's home page. It's hard to believe how often executives, managers, and employees document their stupidity by putting things they shouldn't in writing. Whether it's email, texts, IMs, or anything else that passes through a company server, it can be made public. Even deleting it doesn't make it go away --there's always a backup copy somewhere.

Disparage the company's products or customers. Especially if you're an executive, remember that anytime you're in public -- at a conference, in an airport, even on your own time -- you represent the company and that anyone with a cell phone can record you. The same goes for talking with the media, or anyone else who just might repeat what you have to say. People talk -- just like you do.

Assume private conversations will stay private. Your expectation of privacy is far more limited than you think. If you're at home talking with your family, you're probably okay. I say "probably" because, these days, you never know what your spouse or kid will post on the Web. Other than that, your privacy is so limited you may as well assume that whatever you say will end up on the front page of The Wall Street Journal. That may be sad, but it's good advice.

Get too social with social media. Last year, Bloomberg reported that Scott McClellan, a vice president who had spent his entire 26-year career at HP, tipped off competitors about previously undisclosed details of the company's cloud computing strategy on his LinkedIn profile. Shortly thereafter, he left the company. Coincidence? Maybe, but according to a Forrester Research survey, 82 percent of 150 companies that monitor social media are primarily searching for competitive intelligence. Go figure.