An Affinity Diagram is a technique used in product management to organize and categorize a large amount of information or ideas. It's like creating a bulletin board where you stick post-it notes that represent different thoughts or concepts. By grouping similar ideas together, you can identify patterns and themes. For example, imagine you're brainstorming ideas for a new feature. You write each idea on a post-it note and then group them based on their similarity. This helps you make sense of the chaos and find insights that can guide your product decisions.