Information architecture is a broad and abstract term meaning different things to different people. At its most general, information architecture refers to the way that different pieces of information relate to each other. It can also refer to a representation of these relationships. The term has gained a more specific and widespread meaning on the Internet, where it describes the way that information is presented on a website.
In its more abstract usage, information architecture refers to any system involving the organization of information. The Dewey Decimal System, for example, is a type of information architecture because it attempts to place a large and chaotic range of topics into a linear numerical order. It is no accident that this system was designed for the physical task of placing books on shelves in libraries. Information architecture becomes relevant whenever someone is confronted with the task of squeezing an amorphous set of ideas into a constrained space.
A website is one such space. In the context of web design, information architecture is closely associated with user experience. It describes the layout of a website, with emphasis not on visual appearance but on the structure through which information can be accessed. Menus and hyperlinks are crucial elements of this type of information architecture. Of course, the arrangement of ideas in a single block of text, such as this article, also independently constitutes part of the architecture.
This web-based type of information architecture does not focus on inherent relationships between pieces of information being presented. The issue is how information can be assembled in a way that makes sense to a user interacting with it. A website probably has shoddy information architecture if the users cannot easily navigate to content that interests them.
The Internet makes possible many different models of information architecture. Wikipedia, for example, has an extremely decentralized architecture. Users generate not only the text of individual articles, but the structure responsible for linking articles together. The front page contains mostly random content.
Yahoo! on the other hand, has a more hierarchical information architecture. Its content is sorted into conspicuous categories which are subdivided in specific ways. WiseGEEK largely relies on people using search engines to discover its pages independently; it has less in the way of independent architecture.
The Journal of Information Architecture attempts to tame this unwieldy topic. It aims to address the idea of information architecture scientifically, while at the same time paying attention to ongoing developments in real website design. A recurring theme in the journal, which is relatively new, is a negotiation between theoretical and practical understandings of the concept.