What is the rule of thirds and how is it used in photography?

The rule of thirds is a technique used to achieving a pleasing composition within a photograph or graphic design. Application of the rule involves dividing a scene into three columns both horizontally and vertically, and then composing an image by placing the subject at a point where the lines dividing the columns intersect. An off-centre composition appears more pleasing to the human eye and the rule of thirds is a simple method of achieving such a composition. Most digital cameras feature guide lines which can be turned on or off within the viewfinder or LCD screen to help use the rule of thirds.