Why have the rules of soccer changed today?

One of the main changes, the offside rule, was introduced to prevent strikers from 'goal hanging'. Before the rule was introduced, players could basically stand by the oppositions goal and wait for a long pass, making it easier to score. The offside rule states that a player cannot participate in play if he is behind the second last opposition defender (which may include the opposition goal keeper) and ahead of the ball at the moment the ball is passed. If he does, an indirect free kick is awarded to the opposition team. This rule means that if the defenders are, for example, by the half way line, an opposing striker can't goal hang because, when he receives a pass, he will be in an offside position.