Card sorting is a user testing technique that gives you an insight into how your users group items together, so that you can organize your site as intuitively as possible. Card sorting can help identify not only the most logical paths through your site, but also ambiguous or cryptic terminology that should be reworded. Your test group assembles cards in order of the most logical flow, as well as arranging cards into groups that seem to fit together. These cards contain bits of information from the website. It can be conducted remotely (by mail or electronically) or in-person (one-on-one or in workshops).

Here are some helpful card sorting tips from infodesign.com.au:

• Cards should be large enough to accommodate the names in a font that participants can read easily when spread out on a desk or table — at least 14 point.
• Participants are asked to group items in a way that makes sense to them. Participants may also be asked to name the resulting groups.
• Once all participants have completed the exercise, enter the data in a spreadsheet, and examine the groupings. There will be general agreement about many items, and these groupings will be fairly apparent. For example, all participants may group ‘Technical Support’ with ‘Complaints’ and ‘Product Assistance’.
• You can use cluster analysis to get a pictorial representation of the resultant groupings. An easy way to do this is using IBM’s EZSort program (free from http://www-3.ibm.com/ibm/easy/eou_ext.nsf/Publish/410).
• Pay special attention to items about which a consensus does not exist. Would re-naming the item improve the situation, or does it need to be included in more than one category?
• Ensure that each term is as clear and unambiguous as possible.
• Ensure that you have included all the items you need to categorize.
• Shuffle or randomize cards prior to each participant session.
• Script a set of instructions so that all participants have the same understanding of the process.
• Leave participants alone while they are sorting the cards to avoid placing them under unnecessary time pressure, but make sure they can contact you easily to ask questions or when they have finished
• Provide additional blank cards for people to write group names
• Provide rubber bands so that people can gather groups of cards together.