Using Facebook has become so widespread, it would take too much time and energy to stop employees. Plus, it's also easy to use Facebook on your phone and not your work computer. So, employers should turn a blind eye. The only way to really crack down on it is when people's productivity begins to show.
Facebook is more than games and talking to people. A company can advertise and go through Facebook with comments and ratings concerning their establishment. Companies can find out what their consumers think and correct the problem if needed. They can also find ways to improve their business and know what they are doing right.
Social networking is becoming more and more popular in the workplace. Companies and employers are using it for an additional form of advertisement and a way to give people outside of their company the information they need. I see n problem with this as long as the worker in not playing games and chatting all day.
If any company allows workers to use Facebook, then employees are not able to work properly because Facebook allows them to connect outside world rather than work. That is why we should not give workers that much freedom, since it spoils working conditions. Hence, employees are unable to concentrate on their work.