Should supervisors 'friend' their subordinates on Facebook?

The practice of managers and employees mingling online is rife with legal concerns: What happens if a manager learns too much about an employee? Could what a manager sees be used in a discrimination suit?
There’s also the question of whether the employees will be comfortable with a boss’s friend request.
So what should managers do? HRMorning readers had a lot to say on the subject, commenting on the recent story “Warning to bosses: Don’t ‘friend’ employees“:
AAS: “The only winning move is not to play.” This is true for employees and managers. Ask the police officers in Lexington KY who were fired for posting improperly on MySpace as well as hundreds of other examples of how we as a society have become far too open online. It is far more complex than just friending someone, it has to do with the social fabric of our businesses, and our employees’ day-to-day lives.
Mary D.: I accepted friend requests from co-workers and subordinates. Then one day, a coworker was telling an outside-the-company friend of hers about a new benefit that had not yet been announced. Since she too had many employees as friends, as well as me who knew about the benefit, half the company was alerted and the confusion started. Since then I have cleaned up my Facebook page to friends and family.
Jilly: I worked side by side with my staff for two years, as line staff with them. Then I got promoted to manager. Am I not supposed to be friends with them now? I feel by cutting all ties as friends would cause me bigger problems in the long run with my staff.
Tiffany: I am a supervisor who has friended subordinates and also have been friended by my supervisor on Facebook. The person receiving a friend request does have to accept the request in order for it to be finalized, but what does it say to your boss if you refuse their friend request?
What’s your opinion?