Mouse gestures

What is a mouse gesture?

They can probably be explained better with an example:
Say you wanted to scroll down on a webpage using your mouse. Normally, you would point your mouse cursor to a scroll bar and clicking on it. Using mouse gestures, you would click and hold on to the right mouse button, move the mouse cursor down a little bit, and then let go of the button.

What are the advantages of mouse gestures?

First off, you don't need to point to any user interface element; thus, mouse gestures save time by minimizing mouse movement.
Most mouse gesture programs allow you to customize what your mouse gestures do. For example, if you did not want the down gestures to scroll down, you can change it to do something else such as changing tabs.

How do I add mouse gestures?

For Windows: StrokeIt
For Firefox: All-in-One Gestures
Other: wikipedia entry