Originally Posted by Skydog
It was a known problem for the 3rd generation Kindle (the one prior to the Touch) when it was first released. When standing outside, in sunlight, the fading would occur within a matter of minutes even if the actual air temperature was not particularly high. In that case, the sunlight was the issue. As I mentioned, it was remedied with a firmware update so I would not expect to see it again with any Kindle.
Back then (3rd Gen Kindle) there were some Vizplex eInk screens made by LG that faded in the sun. It affected more then just Amazon. It also affected Sony and others. The only way to get it fixed was to keep trying different units until you got one that didn't use an LG made screen.