Social networking sites like FacebookMySpace and Twitter have changed the way many people communicate and have had an unexpected impact on the workplace. Some companies have instituted policies blocking the popular web destinations, because workers spend too much time chatting with friends and not enough on their jobs.

And many prospective employers now troll the sites to find out what possible hires are leaving out of their resumes and what their attitudes are really like, leading some to lose a shot at increasingly limited openings.

Which brings us to another cautionary tale about Facebook, and an employee who lost her job because of it – even though she wasn’t using it at work.

Last November, a woman in Zurich, Switzerland called her employer, an insurance company, and told them she was too ill to come into work that day. Part of her duties involved using a computer, but she claimed her cure involved lying in the dark and that she was unable to face the lighted screen.

So when a fellow worker discovered the absent employee was chatting on Facebook during her sick day, word quickly spread around the office. And to her stunned surprise, the worker was terminated for her actions, after her bosses said they could no longer trust her word.

The woman admitted she’d been on the site, but only while lying in bed and using her iPhone, an action she insists is far different than looking at it on an illuminated computer screen.

She accuses the company of spying on her and sending a false “friend” request so they could see what she was up to.

The firm maintains a colleague stumbled onto her page last year and discovered the deception – shortly before they decided to ban access to Facebook from their offices altogether.

It’s the latest instance that proves what you do over the web in the privacy of your home and office isn’t really so private anymore. And it may be one more reason workers should be careful of where they go online - and when.

Previous stories:

Cdn. Facebook Users Willing To Let Bosses See Their Profiles: Survey

Provincial Employees Barred From Using Facebook

Restaurant Owner Uses Facebook To Find Customers Who Stiffed Him