One Billion Monitors Vulnerable to Hijacking and Spying (vice.com)

 I recall, during the days of the Hippie generation, of a lady who always did meth.

She would spend hours looking at the mirror and get paranoid, proclaiming,"They are watching me."

Then years and years later I was told about another lady on meth who sat in front of a CRT computer monitor while proclaiming, "They can see us and control us through this."

Turns out they is a bit of truth to some of it...

"We can now hack the monitor and you shouldn't have blind trust in those pixels coming out of your monitor..." a security researcher tells Motherboard.

 "If you have a monitor, chances are your monitor is affected." 

Motherboard's article:

  If a hacker can get you to visit a malicious website or click on a phishing link, they can then target the monitor's embedded computer, specifically its firmware...

The computer that controls the menu to change brightness and other simple settings on the monitor.

The hacker can then put an implant there programmed to wait...for commands sent over by a blinking pixel, which could be included in any video or a website.

 Essentially, that pixel is uploading code to the monitor.  

At that point, the hacker can mess with your monitor...

This could be used to both spy on you, but also show you stuff that's actually not there.

 A scenario where that could dangerous is if hackers mess with the monitor displaying controls for a power plant, perhaps faking an emergency. 

The researchers warn that this is an issue that could potentially affect one billion monitors, given that the most common brands all have processors that are vulnerable...
 
"We now live in a world where you can't trust your monitor," one researcher told Motherboard, which added "we shouldn't consider monitors as untouchable, unhackable things."