Oversharers, take note: Twitter, the trendy microblogging site that has blabbers cataloguing their comings and goings in up to 140 characters, is turning into the latest occupational hazard for those prone to TMI. One indiscreet job seeker learned that lesson firsthand in March when she "tweeted" this careless missive: "Cisco just offered me a job! Now I have to weigh the utility of a fatty paycheck against the daily commute to San Jose and hating the work." Someone at Cisco saw the snarky post and alerted HR, which quickly rescinded the offer.

Trifling as your Twitter updates may seem, don't be lulled into thinking they're harmless, warns Alexandra Levit, author of They Don't Teach Corporate in College. "Always assume that there are work people looking at your posts," she advises. And it's not just the obviously imprudent remarks—about a wicked hangover, your last one-night stand--that could garner a pink slip. Here, Levit's other social-networking guidelines:

Keep your politics private.
Avoid commenting on even school-board races, let alone incendiary topics like the Arab-Israeli conflict. "You just never know what the boss's personal opinion is," Levit says.

Never dish about work.
In March, a British office administrator was fired for calling her job "boring" on her Facebook page. 'Nuff said.

Update only at lunch.
What boss wouldn't question the work ethic of an underling who found time to post her whereabouts every 10 minutes?

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