Blue Coat allows access to some sites and blocks other sites, depending on your configuration. I look at high risk configuring. It lets me allow some applications and block others.
We use the on-premises version.
The Blue Coat proxy-based architecture serves as the foundation for the Advanced Web Security solutions, and is delivered as a cloud service, on-premise appliance or a hybrid of the two. They combine the critical security functions you need to safely adopt cloud and mobile technologies, while strengthening your security and compliance: