Measuring has become more and more important to the job of the information architect. * We need to measure the KPI's of our projects to assure we meet our customers business objectives. * We need to measure the usage of the site to assure it's effectiveness. * We need to measure the users behaviour on the site so we can optimize the information architecture to meet their needs. * We need to measure business parameters such as sales numbers, conversion rates, ... and compare them to the traffic analysis. Measuring becomes essential to define what we do but also to define why we do it. We need to justify and document the effect our work has on the overall business. A new generation of tools allows us to integrate data from traffic analysis, CRM, ERP, with our traditional work of defining navigations, taxonomies, content organization, etc. Most usability tests only include a small sample of users meanwhile there is data available on all of our visitors behaviours, we need to exploit this data and use it to define and refine the overall user experience of our online projects.