Creating efficient communication.
Text marked up for ease of reading, interactive documents, conveying textual information -- whatever it takes.
Visualizing complex concepts
In linguistics, information structure describes the way in which information is formally packaged within a sentence. This generally includes only those aspects of information that "respond to the temporary state of the addressee's mind", and excludes other aspects of linguistic information such as references to background (encyclopedic/common) knowledge, choice of style, politeness, and so forth.
The basic notions of information structure are focus, givenness, and topic, as well as their complementary notions of background, newness, and comment respectively. Focus "indicates the presence of alternatives that are relevant for the interpretation of linguistic expressions", givenness indicates that "the denotation of an expression is present" in the immediate context of the utterance, and topic is "the entity that a speaker identifies, about which then information, the comment, is given". 
Structuring Information With Mental Models
We all know that a curious person can more efficiently absorb information when it is well structured than when it is arbitrarily scattered. The question that every information architect then asks is, "How might I best organize the information for that person?" This question contains three issues:
- what structures are useful for organizing information in general,
- what structures are useful for organizing that information, and
- what structures are useful for organizing information for that person.