As a manager what restrictions would you put on personal media use at work? Why?

As a manager what restrictions would you put on personal media use at work? Why? 

As a manager I would be as strict as I could regarding the use of social media at work. The reason for this is that many problems can be created by using them ranging from work related ones to personal ones that develop in the workplace because of the personal media usage. Additionally there is the issue of infighting, gossip and a whole plethora of inappropriate actions that can take placed when there is excessive personal media usage at work. In reality there is no reason to use this at work and I would therefore find it ludicrous to find arguments for using it. At work people should be working not playing. They can do that on their own time and on their breaks. If they are using it at work that means they are distracted and they are not working. Past this simple fact alone I would see no reason to allow there to be open social media usage or even personal phone usage at work. That should be for emergencies and I would let employees to know that they can use the company line for emergencies. Overall, my stance would be that there is no need for cell phone use at work, no need for social media use at work during paid hours and absolutely no use of company computers or wifi for personal social media use.