Do you know who your friends are?

A recent news story reported that a St. Louis high school principal was fired for masquerading as a student on Facebook. The fictitious student was named “Suzy Harriston,” and it seems she’d had a Facebook profile for over a year before the firing. Following a recent controversy over the dismissal of a football coach, “Suzy” asked over 300 of her classmates to be friends. In April, a 2011 graduate of the school outed “Suzy” as Clayton High School principal Louise Losos. The following day, Losos was placed on leave. She has now been fired.

“Suzy Harriston,” officials say, was never a student at Clayton High, and no one has ever been able to identify her as an actual human being.

All of which is a sharp reminder that the Internet can be a dangerous place. Do you know who your Facebook friends are? Do you know, really know, who’s reading your most intimate secrets? What would be the fallout if you wrote some pretty rotten things about your math teacher, and the teacher, disguised as a “classmate,” read every single word?

I’m not saying you ought to be paranoid the next time you friend someone. I just want you to use a little common sense. That perky little sophomore who likes icanhascheezburger.com may not be the person she claims to be.