The Scout is the “twitch” class of Team Fortress 2. He is the fastest of all the classes and has the ability to double-jump. This, coupled with his Scattergun, makes for quick point capture and assault, and can also inflict massive damage if fired at close range. The Scout is traditionally used for objective acquisition, i.e. capturing control points or flags. However, Scouts are particularity good at enemy harassment and swift territorial denial.
The scout’s speed makes him invaluable in making flag runs on CTF maps and he also counts as two people when capturing a control point or when moving a Payload.