The Three-Click Rule is an unofficial website navigation rule that suggests that users should be able to find any information within a website using no more than three mouse clicks.

Many user experience (UX) professionals believe that users of a site will become frustrated and leave if they cannot find desirable content within the three clicks. Therefore, if a website follows this three-click rule, navigation is more efficient.

Read the whole glorious thing…  User Experience Myth Or Truth: The Three-Click (Or Tap) Rule.