Execute commands without using the keyboard, menus or toolbars. Instead, the user holds down a mouse button (usually the right one), moves the mouse in a certain way to form a gesture, then releases the mouse button.
This provides tree-style tab bar, like a folder tree of Windows Explorer. New tabs opened from links are automatically attached to the parent tab. If you often use many many tabs, it will help your web browsing because you can understand relations of tabs.