I have seen a lot of the same questions come up recently and thought that it would be a good time to put some simply explained rules out there.
If you see a lot of questions about a similar rule come up, why not make a thread in here and explain it in the simplest of ways? I'm hoping we can de-mystify some of the rules of this great game.
There is a content thread that is stickied in the main Rules Section... add what subject you wrote on there.