As I sit here and send this from work, where I am responsible for monitoring our network, I think both sides of this argument have some valid points.
While there is certainly room for rampant abuse with the granting of open access to the internet, there are some employers that are taking things too far. For example, the constant monitoring of web/email traffic is a touchy issue that is sparking more than one lawsuit regarding privacy. Despite what many employers would like to believe, they don't 'own' the employee while they are at work.
On that vein, if as is common in the high tech industry, employers demand longer working hours and the sacrificing of personal time for the company, they had better make the workplace a more comfortable place to be.
While we have discontinued our internet monitoring for the time being, I found there were few instances of abuse. There was the odd accessing of porn sites, usually from PC's accessable by shopfloor workers. The only major spike in usage was a dramatic increase in accesses to job-hunting websites after they announced laying off 1/3 of the workforce....8)
Anyway, my personal policy is that I will do blind monitoring (track accesses by IP with no names) until I notice something that concerns me. This allows for users' privacy and the protection of the company from usage that could leave us liable. (Which is our main concern, we have a policy of leaving employee productivity up to each employee/manager) If the work is done, cut loose.
Cheers
Chris Hall