You might have heard that this week Mark Zuckerberg and Priscilla Chan announced that they’re going to give away 99% of their Facebook stock in hopes of making the world a much better place for their newborn daughter and her generation. Now, I just want to be right up front with you. I have no inside information about this fascinating development. But what I do have is inside information, the inside story, on a gift that this couple made five years ago in their first act as philanthropists.