In his latest Alertbox column/newsletter usability guru Jakob Nielsen shares best practices and ideal numbers of participants for effective card sorting in contet (re)organization processes. "A classic mistake is to structure the information space based on how you view the content -- which often results in different subsites for each of your company's departments or information providers. Rather than simply mirroring your org chart, you can better enhance usability by creating an information architecture that reflects how users view the content." Card sorting, is an effective method utilized to apply user-centered design principles to the information architecture/content (re)organization process. Representative end users are given a stack of cards labelled with the different content items/categories that need to be classified. As end users group, prioritize and comment their choices, information architects and site designers get a unique perspective of what end users think, want and where they expect to find it. Card sorting is a generative method: we don't yet have a design, and our goal is to find out how people think about certain issues. There is great variability in different people's mental models and in the vocabulary they use to describe the same concepts." For those of you interested in finding out more about the actual card sorting exercise specifics, here is an interesting set of card sorting tools and articles, which may greatly facilitate your initial discovery process. When carrying out a card sorting session, selected end users organize the cards into clusters and then label these groups. The result (for example a taxonomy) serves as an interesting input point for defining the basic Information Architecture approach of any web site. In card sorting there are two main techniques: Open Card Sort and Closed Card Sort. In Open Card Sort, users can define their own categories (this method is often used early in the design lifecycle). In closed Card Sort, the categories are predefined (this method ist mainly used when a existing website should by restructured).