Web filtering is considered to be a multi-appliance tool. We all understand the theoretical reasons of its inventing – protecting children from Internet pornography and avoiding hidden threats. In fact, today’s filters’ appliances would be a surprise even to their creators. Internet censorship becomes more and more known problem and applies to more countries. A need for control is common. Consider anti spam that is being installed on company’s computers. What are the reasons of restraining Internet usage at work? Is it really a matter of workers’ efficiency? In fact, workers, whose efficiency would be so easily modifiable, usually don’t work with computers, so Url filtering at workplaces have nothing common with real care of work results. Then, why is it so common? It’s a matter of relation between worker and his manager. Managers used to think that atmosphere of total control favors better results. In fact, it has totally opposite consequences. Beside controlling itself, filtering at work guarantees the same profits as with any other computer – a powerful support for avoiding Internet threats. Infecting a company’s network might be a real problem and it’s the first real reason why filters at work should be enabled.