According to The New York Times' Alice Rawsthorn, the skull and crossbones on a pirate flag, a symbol adopted in the early 1700s by pirates worldwide, may be an astonishingly successful exercise in collective branding design still recognizable today.

The key to its success was clarity of meaning, which is an essential element in every effective branding project, and any other form of communication design. Just as Nike's "swoosh" logo makes us think of speed and the horse-drawn carriage in Hermès's identity screams posh, the sight of a skull and crossbones on a ship's flag signaled one thing to 18th-century sailors like those on the Poole or the merchant vessels they were protecting: terror.

The image above comes from the Jolly Roger's entry on Wikipedia.