What does ALL-I mode mean? I've started seeing this term mentioned in camera specs but have no idea what it means. It somehow relates to recording video.

Can somebody please explain where does it come from and what it means?

Here's all I found:
http://www.dslrnewsshooter.com/2012/03/02/canon-launch-5d-mkiii-headphone-jack-all-i-recording-and-better-controls/


  The compression system is the same as the 1D X and supports the higher
  bitrate ALL-I compression system alongside a more regular IPB option.
  The ALL-I mode is supposed to offer easier editing due to it’s less
  compressed nature, whether it also offers improved quality over
  standard IPB remains to be seen.


Also, the upcoming Panasonic GH3 has 


  Video Bitrate 50Mbps (72Mbps ALL-I)


Never seen this thing before...
This will get migrated but the short answer is that ALL-I stores every frame in it's entirety, whereas other methods store a certain number of keyframes in entirety, with the other frames stored as the difference to the keyframe.