The idea that Mark Zuckerberg has to engage in an action "for the publicity" is funny. Especially when it comes from journalists. Facebook is effectively the biggest media organ out there at the moment.
Being famous doesn't necessarily mean that you have a good reputation, people tend to be wary of tech billionaires, so even them can use some publicity to improve their public image.
It seems that it worked in this case.
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 :)