What you write on social media could be online forever, and in some cases, might even get you fired. 

That's the warning Richard Alexander of the Employers' Council is giving people after the firing of an employee at Corner Brook Pulp and Paper.

The former mill worker took to Facebook with an obscenity-filled rant about management last fall.

Alexander said once something is posted on the web, it can quickly spread out of control.

"It's not private, it is public and everybody in your circle of friends can share that, can pass it along to others and before you know it …it goes viral and people's lives are impacted by your comments," said Alexander.

Alexander calls the Corner Brook case extreme, and said the firing of the mill worker was — to this knowledge — only the second case in Canada where someone was fired over comments made on Facebook.

But there are more examples.

In 2010, the B.C. Labour Relations Board ruled in favour of a car dealership that fired two employees for posting derogatory comments and threats against their bosses on Facebook.

In London Ont., a man who posted negative comments about the death of Amanda Todd, was fired from his job after a woman alerted his employer.

And most recently, two Toronto firefighters lost their jobs after posting sexist remarks on Twitter.