Mark Zuckerberg
Mark Zuckerberg and Priscilla Chan have welcomed a baby girlFacebook

Mark Zuckerberg has revealed that he plans to give away 99% of his $45bn Facebook fortune. The Facebook founder made the surprise announcement on the birth of his first child. His wife Priscilla Chan gave birth to a healthy daughter named Max on 1 December. In an emotional letter to his new baby posted on Facebook, the social network's founder and his wife said they wanted to help make a happy and healthy world for her and all children.

The emotional post begins: "Your mother and I don't yet have the words to describe the hope you give us for the future. Your new life is full of promise, and we hope you will be happy and healthy so you can explore it fully. You've already given us a reason to reflect on the world we hope you live in.

"Like all parents, we want you to grow up in a world better than ours today," the note reads. To do that, the note says, will require advances in health, education, technology, and equality. To do that will require "long term investments over 25, 50 or even 100 years," he explains.

Some of the initiative's goals also align with Facebook's Internet.org project, which aims to establish zero-rated internet access in poor countries. "Many of the greatest opportunities for your generation will come from giving everyone access to the internet," the letter continues. "The internet is so important that for every 10 people who gain internet access, about one person is lifted out of poverty and about one new job is created."

The initiative focuses on two central goals: advancing human potential and promoting equality. The first goal is defined as "pushing the boundaries on how great a human life can be," including initiatives on medicine, economic opportunity, and access to information. The second group of projects focus on alleviating poverty and empowering traditionally underrepresented groups. "Our society must do this not only for justice or charity, but for the greatness of human progress," the letter states.

He concludes the heartfelt letter saying: "Max, we love you and feel a great responsibility to leave the world a better place for you and all children. We wish you a life filled with the same love, hope and joy you give us. We can't wait to see what you bring to this world."

Last year, the couple pledged $25m to fight the spread of Ebola, with the aim of preventing a larger public health crisis "like HIV or polio." Zuckerberg also individually donated $100m to the Newark public school system, although a significant portion of the money was swallowed up by bureaucratic inefficiencies.

The details of the donation are still unclear, but the couple has already registered a Facebook page for an organisation called the Chan Zuckerberg Initiative. It is set to be one of the largest charitable pledges in history.

Zuckerberg, had previously opened up about the couple's difficulties in getting pregnant and later shared their joy at the news that Priscilla was expecting with his 33 million Facebook "friends" with a 'pregnancy announcement.' Last month, he announced that he would be taking two months off for paternity leave.

Zuckerberg and Chan met at university in 2003. They married seven years later on May 19, 2012 in a quiet ceremony in their backyard. They announced their nuptials - like their pregnancy - with a post on Facebook. Zuckerberg is the 9th richest person in the world according to Forbes.