|Tor Norretranders is an acclaimed science writer who found an international readership with his landmark study of consciousness, The User Illusion.
From yee Wiki, " Exformation (originally spelt eksformation in Danish) is a term coined by Danish science writer Tor Nørretranders in his book The User Illusion published in English 1998. It is meant to mean explicitly discarded information. However the term has also been used for other meanings related to information, for instance “useful and relevant information” or a specific kind of information explosion.
Meaning as proposed by Nørretranders
Effective communication depends on a shared body of knowledge between the persons communicating. In using words, sounds, and gestures, the speaker has deliberately thrown away a huge body of information, though it remains implied. This shared context is called exformation.
Exformation is everything we do not actually say but have in our heads when, or before, we say anything at all - whereas information is the measurable, demonstrable utterance we actually come out with.
If someone is talking about computers, what is said will have more meaning if the person listening has some prior idea what a computer is, what it is good for, and in what contexts one might encounter one. From the information content of a message alone, there is no way of measuring how much exformation it contains.
In 1862 the author Victor Hugo wrote to his publisher asking how his most recent book, Les Misérables, was getting on. Hugo just wrote “?” in his message, to which his publisher replied “!”, to indicate it was selling well. This exchange of messages would have no meaning to a third party because the shared context is unique to those taking part in it. The amount of information (a single character) was extremely small, and yet because of exformation a meaning is clearly conveyed.
Thought, argues Nørretranders, is in fact a process of chucking away information, and it is this detritus (happily labelled exformation) that is crucially involved in automatic behaviours of expertise (riding a bicycle, playing the piano), and which is therefore the most precious to us as people.
—The Guardian, September 1998"