Most networks of significant size use a forward proxy server to filter their Internet traffic. This is essentially a box that sits out near the edge of the corporate network; whenever client computers in the network try to access the Internet, their requests are sent out through this server. Doing this enables companies to monitor Internet use, restrict browsing permissions, and keep many forms of malware at bay. When implementing a proxy server, one of the big questions is always "How do we enforce the use of this proxy?". Some solutions do a default route through the proxy server so that all traffic flows outbound that way at a network level. More often, though, it is desirable for the proxy server settings to be configured at the browser level because it is likely unnecessary that all traffic needs to flow through this proxy, only the browser's web traffic. In these cases, you could certainly open up Internet Explorer options on everyone...