Many years ago when the Internet was being adopted by businesses, I worked for a company that was so scared of the impact of the Internet to its business model that it not only refused to embrace the Internet, it also banned its employees from even using it as a business tool (I left the company soon after and so did many others – the company is still in business but it realized its mistakes and now uses a web-based business model).
The Internet can scare companies in many ways, and while it is hard to imagine a business being able to survive without it, there are many ways to “waste” time too. Well, there have always been many ways to waste time at work – all the way from just goofing off to chatting with colleagues to taking extended breaks. In other words, it is somehow naive to imagine that your white-collar workers will work 8 hours like a machine.
In my opinion, you may be doing more harm than good by trying to limit access to MySpace or FaceBook (Related: Should you monitor your employees?) – you lower the morale of your employees but if your employees want to goof off, they will any way. It is much better to focus on developing better job descriptions, motivating employees to excel at work, and rewarding them for performance.