Peter- the rock?

Peter- petros...a rock that can be easily moved

The Rock- petra...a massive, unmoveable rock ledge

"But what about you?" he asked. 'Who do you say I am?'
Simon Peter answered, 'You are the Christ, the Son of the living God.'
Jesus replied, 'Blessed are you, Simon son of Jonah, for this was not revealed to you by man, but by my Father in heaven. And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. 
I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven."
(Matthew 16:15-19)

1. What was revealed to Peter by the Father.

2. Is it possible Jesus was intentionally showing the difference between Peter, the stone, and Jesus the massive rock ledge?

3.Why does Jesus always say you when talking to Peter, but uses this when speaking of the rock. If the rock was Peter, it would be much clearer to say you instead of this. Then there would be no question.

4. Why would Jesus intentionally use a word for rock that means something different than the word for Peter?

What does it mean?