Often, employers implement Internet usage policies in order to control how much time their employees spend using the Internet for personal tasks, such as online shopping, general web surfing, or answering personal email. Internet usage policies also protect companies from risks associated with Internet usage. Employees with unsatisfactory knowledge of common security measures could potentially infect company computers with viruses or other malicious programs that could lead to costly and time consuming data loss. Employers often have employees sign Internet usage policies; these policies should clearly state what is and is not allowed with regard to company computers, as well as the penalties for breaking the rules. Some employers may take things a step further by using tracking or snooping programs to monitor their employees Internet usage. Generally, courts have given employers a great deal of discretion with regard to monitoring what occurs on company computers. Employees should be aware that an email sent from a company computer may not be private, and may be read and reviewed by their employers.