Andrea Wiggens has written a good article over at Boxes and Arrows discussing why IA’s need “to understand why visitors come to the site and what they seek, so that the content can be best presented to meet user needs and business goals.”

Using heuristics
Providing a context for heuristics is the most useful application of web metrics in a site redesign: a framework for measurement is critical to future evaluation of the success and value of strategic but intangible investments like information architecture. Analyzing pre-existing web traffic yields insights to user behavior and measures how well a site meets user needs. By comparing analytic data to an information architect’s heuristic evaluation, a basic validation emerges for otherwise subjective performance measures. In addition to heuristic validation, web analysts can use the information to engineer effective key performance indicators (KPI) for future evaluation, and the information architect can use the information to provide direction for the design.

(Via Boxes and Arrows.)