Business Internet usage is commonly regulated and monitored in order to protect companies from the many risks associated with Internet usage. Protecting private information and company data is a chief concern in regard to business Internet usage. Companies are often responsible for many networked computers, which may all be connected both to each other and to the Internet, causing complicated security concerns. Information technology specialists are often employed by businesses to oversee and troubleshoot business Internet usage. Viruses and data loss are common risks associated with many businesses in the 21st century. Lost time and profit loss can also occur due to technical issues affecting business computers. Personal Internet use by employees while on the job is also a common concern, and can pose an entirely different set of risks. Many employers have specific guidelines regarding business Internet usage among their employees, and may restrict or monitor their employee's Internet usage.