Kwasnick (1999) identifies four classificatory structures: hierarchies, trees, paradigms, and facets.

Hierarchies divide and redivide things into groups where each new group is a sub-species of its parent group; everything that is true of a group is also true of its sub-groups and so on down (Kwasnick 1999, 25). The Linnean taxonomy of living things is the classic example of this.

Trees, in contrast, do not have the rules of inheritance (Kwasnick 1999, 30). For example, North America contains Canada, the United States, and Mexico, and Canada contains ten provinces and three territories, but Ontario is not a kind of Canada, and Canada is not a kind of North America

There is a fundamental difference in the activities of browsing to find interesting content, as opposed to direct searching to find relevant documents in a query. It is similar to the difference between exploring a problem space to formulate questions, as opposed to actually looking for answers to specifically formulated questions

Merholz does not use the term “folksonomy.” He has written on his personal web site that the term is inaccurate due to its derivation from “taxonomy,” which he argues tend towards hierarchy and control. (Merholz, 2004) (See also Taylor, 2004, for discussions of problems and disputes with the term “taxonomy.”) Merholz prefers the term “ethnoclassification,” which is what he uses in his article, and there is no mention of “folksonomy” to be found. Ethnoclassification is also inaccurate, because as discussed, what is happening is quite unlike classification and far more like categorization.

f a top-notch information architect was on your design team, she categorized and classified your content, then arranged it in one or more taxonomies to support clean drill-down paths.

The canonical example of a faceted directory is an ecommerce site like Wine.com, where visitors can browse by wine type, region, winery, or price

Research benefits architecture most when it seeks to define the problem we must solve. Research benefits architecture least -- and can actually produce bad results -- when it seeks to define the solution itself.

When most people think of the job of being an editor, I think they imagine someone hunched over a desk, red pen in hand, marking up an endless stream of text, cleaning up split infinitives and dangling participles and the like. But the editorial role and the editorial discipline are two very different things. While there are definitely some people who specialize in this sort of work, there's usually much more to being an editor. In the broadest sense, an editor's job is to help writers make their writing more effective. This involves grammar and punctuation and word choice, sure, but a huge part of any editor's job has to do with creating effective structures. An editor might be responsible for structures at many scales, from the encyclopedia down to the textbook down to the article down to the paragraph down to the sentence. Like the editor, the information architect is concerned most fundamentally with creating information structures. But the discipline of information architecture views this responsibility in a very different light. In the world of information architecture, all structural challenges are currently viewed as variants of the same problem -- the problem of information retrieval.

If you asked an editor at a magazine or a newspaper if the structure of her product had been tested with readers before its publication, she would laugh at you. To her, developing effective structures is a matter of exercising her professional judgment -- judgment honed through years of trial and error and hard-won experience with her craft. To her, the proof of her effectiveness in her discipline is her ability to exercise that judgment. To her, that judgment is the very reason for the existence of her role. To her, the idea of abandoning that professional judgment and recasting her role as a conduit through which research findings become structures would be simply absurd. And you know what? She's right.