Pay it forward is a rather unique method of changing the world. It's basically states that you help someone in anyway that you can, you then tell the person to pay the favour forward creating a chain reaction of awesome world changing goodness.
The main idea behind the concept is to change the world with as little personal effort as possible, something we at cracked highly commend. This is also a literal application of the butterfly effect meaning the coffee you buy that hobo could save the president or lead him on a crushing personal decent into drug and alcohol abuse. What matters is that you tried to make the world a better place, if only for a brief moment regardless of how you action pans out in the long term.
It is widely encouraged to try to pay it forwards as much as possible mainly through random acts of kindness. This means that you are encouraged to perform a least one unexpected act of kindness to a stranger each day, telling the stranger to simply pay the favour forward (laughing hysterically and then jumping into the batmobile is entirely optional). Cracked is all for changing the world and encourages anyone reading this page to do something nice for somebody else.
Paying it forward is a popular method of thinking as it requires little personal effort and gives the follower a huge helping the world boner. Be careful not to fall into the trap of smugness, some people believe that by following this concept they can brag about it and generally act like dicks. Cracked gives the following advice, dont be a dick.
The concept was brought to public attension in a fairly overlooked film entitled "pay it forward". The film features Jon Bon Jovi as an alcoholic, wife beating dead beat dad (say that five times fast). It shows a young boy trying to change the world using this concept, only to be brutally stabbed by a child with dodgy accent. Needless to say the film truly captures the spirit of karma, that doing good things and trying to improve the world will get you stabbed.