A Facebook post from Mark Zuckerberg has attracted attention for ‘all the wrong reasons’.

The social network’s CEO was celebrating Instagram’s increasing popularity – it now has over 500 million monthly active users – but this milestone was soon eclipsed by something altogether different.

In the image that accompanied the post, what we understand to be his laptop can be seen in the background.

So far, so normal. However, on closer inspection, the webcam and the audio jack on his Macbook appear to be covered by tape.

Needless to say, this cautious approach to security has caused quite a stir online, with many speculating as to why Mr. Zuckerberg has done this.

Those up to date on security will know that this is not a new thing, nor is it demonstrative of overcautious behavior. For example, back in April, the FBI’s director, James Comey, revealed himself that he tapes over his webcam. Speaking at an event at Kenyon College in Ohio, he said: "I saw something in the news, so I copied it.

“I put a piece of tape — I have obviously a laptop, personal laptop — I put a piece of tape over the camera. Because I saw somebody smarter than I am had a piece of tape over their camera."

The reality is that some cybercriminals do try to gain access to laptop webcams, turning them into “a tool for spying”.

 This is often done using a type of malicious code called a RAT or Remote Access Terminal.

According to ESET security researcher Stephen Cobb: "The continued use of RATs by the ethically-challenged is one more reason to keep your anti-malware protection up to date."

When Katie Rogers of the New York Times, asked ESET security researcher Lysa Myers about the practice of laptop camera taping, she noted: “If you were to walk around a security conference, you would have an easier time counting devices that don’t have something over the camera.”

When the Times asked Mr. Cobb if the risk of webcam eavesdropping was limited to people who are billionaires or high-ranking government officials he noted that, "for people who are not CEOs, the threat is people scanning the internet for accessible webcams for a range of motives, from voyeurism to extortion”

Covering a webcam is popular among readers of WeLiveSecurity. A live poll currently reports that 44% of people cover their built-in camera.