This practice of hacking webcams is known as camfecting. And with the introduction of integrated cameras in laptops this danger is increasing day by day. So it is important that we initiate necessary steps to save ourselves from landing into bigger troubles posed by hackers.
Not only Zuckerberg but even FBI director James Comey uses tape as the simplest way of barring hackers from remotely spying into your life as it blocks out everything that can be seen through the lens of your webcam. However, if you need to use the built-in camera anytime, you first need to clean the sticky residue over the lens.
The most common way people hack your webcams is with click-jacking. This means they create an ad or an offer that is too good to be true. You click a button or a link in the ad, and there is an invisible script located on that ad that you have just clicked. This then activates the webcam. Then there is another script that disables the light so you are unaware they webcam is turned on.
So if you use your webcam a lot for video chatting, then you could simply power down your laptop as even the best hacker in the world won’t be able to see anything if you are not using your machine.