Read a couple articles last week on the impact on worker productivity of Cyber Monday (the black Friday online).  I am a libertarian techn-evangelist and believe everyone ought to have the right to use the internet freely at work and where ever they are however what do you do when people abuse this freedom? .... 

The old adage trust but verify seems to be the best bet.  People using company resources on company time will be monitored, the advances in technology have made it so that a three year old can practically silently monitor website usage, emails, IMs and with viop calls.  Does that mean you should spy on your employees?  NO - It DOES mean that it should be made clear to employees that at work, on company time and company equipment  - what they do the company has the right to know.

Give them freedom but make sure its not being abused by verifying how that freedom is being used.   And if it continues to be abused then block away, but block wisely, some sites like Facebook, MySpace can be tools or can be terribly abused.