I agree with the general sentiment here. Are your employees task-based or project-based? If they mostly have tasks to deal with, then I'd guess the internet use is going on when there are no immediate tasks to be handled. If, on the other hand, they could be getting some work done on projects and choose instead to update their Facebook pages, then I'd agree it's a problem.
Reducing the size of the internet for your employees is harsh. It may be deserved, but it's still harsh. It may lead to reduced morale and less productivity despite the reduced distractions.
Proceed with caution.
