Cyber slacking can be a problem with telecommuting employees because it's difficult to verify their computer activity, but internet contracting companies like oDesk and Elance address the issue by using software that logs keystrokes, tracks mouse movements, and takes random screenshots. In order to offer some flexibility for normal human behaviors like chatting or watching silly videos, oDesk allows employees to view the screen captures before their employers and black out anything NSFW (Not Showing Feverish Work) at a cost of one-sixth of their hourly wage.
This kind of tracking software isn't limited to online work environments either; programs like Tahometer, Time Doctor, Worksnaps, and Refog allow similar tracking (including screenshots) of workers in an office as well. It sounds terrifying, but plenty of people are not afraid of the network nanny — oDesk has 1.4 million contractors competing for 250,000 jobs and Elance has half a million contractors contending for 55,000 jobs, according to the New York Times Bits Blog. If you don't like the idea of being monitored so closely, you can always just get a job where you're paid by the task.