From John A. McArthur, Ph.D., an assistant professor and director of undergraduate programs in the Knight School of Communication at Queens University of Charlotte (jamcarthur.com):

Facebook is changing the face of our private lives. The impending release of Facebook Timeline and Open Graph blurs the lines between private information and public announcements. Some critics suggest that Americans need to realize that all information shared online is public - regardless of the privacy controls we believe we have.

Next time you tweet or update your Facebook status, make a choice about who you want to be in the public space of the Internet. In our global village, are you a town crier, a costermonger, or just the village idiot?

Media theorist Marshall McLuhan suggested 50 years ago that electronics would lead us toward a global village - a world made smaller and more social by rapid advances in communication technologies. Many people believe we now live in that interconnected village of loud citizens who publicize various aspects of our lives.

Sharing ourselves publicly is not a new phenomenon. In medieval towns and villages, three types of people could often be found yelling in the streets.

The first, the town crier, was responsible for sharing the daily news. He walked the streets ringing a bell, shouting, "Oyez, Oyez!" His responsibility was to make announcements for the court, the government or other influential organizations.

The second, the costermonger, was often known as a hawker or street vendor. She could be heard singing advertisements for her goods or trade. Whether selling strawberries, flowers, or clothing, this savvy businessperson used her voice to make a living.

The third was known around town as the village idiot. He ran through the streets making a joke or serving as one. His was the voice of the jester, the merrymaker, the town player or the buffoon.

In towns, there were also citizens. These townspeople weren't often shouting. Instead they listened, discerning between the voices on their streets. They used their voices sparingly to join in the fun or to talk among themselves.

In the global village, we give voice to our stories on Twitter and Facebook. We shout on YouTube and peddle our wares on eBay, Etsy, and blogs. We even identify our streets on Foursquare.

Each of us must make a choice about our voice - the role we choose to play in our global village. Like the town crier, we could advance the news of the day. As a costermonger, we might be found practicing our trade. And many of us, like the village idiot, just add to the noise and festivity of our town. All of these voices can benefit the village.

However, the more important role in our global village is the one of citizen. The citizen listens, thinks, evaluates, and then joins in the discussion. My hope is that, like the citizens of the villages of old, each of us can learn to distinguish between the voices of the crier, the costermonger and the idiot. Only then can we become engaged citizens, fully participating in the global village.