It could be difficult to manage a number of employees who have PCs at their desks. You may observe your employees. Nobody just sits around. And at the same time they could be simply browsing porno sites or reading news. Should you try to spying on them? Or is there probably a more honest and transparent way of computer monitoring?
In the past the choice for superiors who wanted some control was limited. They had to install spyware. Spyware is the name for software applications that make screenshots, copy text entered from the keyboard, watch over traffic. So you get control. The problem is that you might lose something else. Spying in general is a very bad and dangerous business.