I've heard other criticisms that he is just going to give it to a charity fund in a similar manner to other billionaires who place their children at control of the charity and then use it as a way to pass on wealth to their kids without any taxation. Not entirely sure of the credibility of the claim that Mark is doing it, but I do know that this scheme has been tried and worked for others before.
Mark Zuckerberg annouced that he is going to give away 99% of his facebook wealth ($45 billion) over his lifetime.
He announced guiding questions:
It's interesting that "live much longer and healthier lives" is on the list. Larry Page seems to divert money inside Google into Calico for anti-aging tech. Under Cook Apple also invests into health.
The future seems looking good :)