cheers for the technical info m8, i love to learn. but aparently (think it was jerry jerry who quoted it) samsung have admitted to a problem with burn in on the s3 and recommend using low briitness (not much use to our friends in horrible sunny places lol) and dont know if its rumour but aparently theyl replace affected panels if it impaires normal use.
so would burn in only be visible with pixels at high R/G/B level and not visible with them at zero (true black)?
Honestly, I think Samsung took something that was just people complaining about something they thought they saw and then hysteria made worse and made an "issue" out of nothing so people would keep quiet. The only way an LED can burn is if too much power is fed across it so people with root brightness changers may have turned the brightness up higher than it should have or something damaged the screen outside of normal conditions.
The people that had legitimate problems seemed to arise from having the brightness up all the way and leaving the screen on for a majority of the time. While several people said this did not affect their phones, the heat, power (based on the color/contrast of the image on the screen), and other factors may have caused the LED's "backlight" capability to become reduced, lowering the sharpness between pixels and reducing the brightness possible for those pixels, thus creating the image distortion they saw.
As for one bit of interesting information that I read, the status bar is usually the only part of the phone that is not burned in by people with bright screens and images on all the time. Since the status bar is mostly black, the rest of the screen with the vibrant images becomes worn, but the user assumes the smaller portion of the screen is the damaged portion.
It looks like no one knows for a fact what causes it or how to replicate it reliably. It may just be a property of the driving voltage, switching, and material of (AM)OLED based screens.