As more and more of us get online and share information, the notion of “privacy” becomes a quaint expression. And when you mix your private and professional lives — especially online — the distinction between the two blurs.

That’s a lesson some have learned the hard way. In North Carolina last week, a waitress lost her job after she complained about a customer’s tip on her Facebook page. In our own community, parents last week were passing around printed pages from a local teacher’s Facebook page, on which she had made what parents said were derogatory comments about students, particularly special education students.

Tales of employees brought down by gossip or unprofessional behavior have always been around — but the difference in the Internet age is that such information not only spreads like wildfire, it can also be printed in black and white.

Experts advise that all professionals should keep the lessons of Internet privacy — or non-privacy — in mind when using social media sites like Facebook. Such sites can be a great tool for keeping in touch with family and friends — and even for making professional connections — but you always have to remember that your audience isn’t as small as you might think.

And when you consider that someone you consider a friend — either online or in real life — can easily post a photo of you or print a comment you’ve made, what you do at any given time could be reflected online.

At a time when it is tough enough to keep or get a job, keeping your online brand clean is essential.

It’s a tough lesson, and it is unfortunate that some have learned the hard way.