Good for Gates, even if he is $18B poorer.
As for his charities that's can just be PR to get people to say "Wow, what a generous man, I'll support his company". He will also eventually get a noble prize for it.
On the other hand he can really be a nice guy and gives it from the heart but the publicity surrounding each donation negates this in my opinion.
I will take a bit of both for now.







