The idea that new media is constantly being re invented from older medias, rather than new media appearing out of the blue. A good example of remediation would be digital cameras as they have evolved from the camera obscura to complex DSLRs.
Known as the invisible media, where the medium can be forgotten. A good example of immediacy is virtual video games. As the idea of the games is to get so involved within the virtual reality that you believe that you are in fact a part of the game.
Is the opposite of immediacy and is realising the difference between medias and knowing that what you are experiencing is part of a medium. For example, watching TV and at the same time updating your status on Facebook. You know that you are using different medias and that there are boundaries between them.