Why is Jn. 3:16 so well known?

Ever wonder why Jn. 3:16 is the best known verse in the Bible? It's rather ironic to think that this verse is the one that is shouted from the house tops, so to speak, when in its original setting it was spoken privately to Nicodemus who came to Jesus by night. In this study we seek to answer the question - Why is John 3:16 so well known?
I. Because it reveals the heart of God in His love.
II. Because it reveals the mind of God in His plan.
III. Because it reveals the response of man in his faith.