Card sorting is a technique in user experience design in which a person tests a group of subject experts or users to generate a dendrogram (category tree) or folksonomy. It is a useful approach for designing information architecture, workflows, menu structure, or web site navigation paths.

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Specific uses of card sorting

Brand Deck

Online tools for card sorting

Card Sorting Software | Optimal Workshop

How to Use Trello for Card Sorting - Niaw de Leon