The Rule of Thirds claims that a composition with the subject placed on thirds-boundaries of an image is more interesting than a composition that has the subject in the middle. The term rule is misleading. It’s a guideline that can help you in certain situations. Nothing more. Nothing less.
More generally the rule of thirds is a good guideline for how to make an image more interesting. It might lead the photographer to move the subject away from the dead centre of the image to make room for an interesting background element. Or it might mean cutting off part of the main subject to reveal an interesting detail. The rule of thirds is a useful tool for helping photographers think more about composition.
*none*