Exformation is "explicitly discarded information".
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.
In my opinion, the more exformation you generate, the better your writing, design, art, photography, or blogging will be. (thx, ze)