"Information architecture is a combination of art and science to organize information into a functional and usable format, allowing someone unfamiliar with the information to easily find what they're looking for."

Digital Web Magazine - The $ and Sense of IT: Making Cents from Information Architecture
When it comes to Web development, everybody has taken short cuts over the years. This holds especially true when working on low budget projects. One of the most costly short cuts is skipping the development of a sound and highly functional information architecture (IA). While this short cut may take several forms, failure to devote enough resources and to document it properly will cost the owner of the Web site more than just a few cents.
http://www.digital-web.com/columns/dollars/dollars_2003-01.shtml