I know I directly benefited from a Carnegie library as a kid. With philanthropy at this scale there is potential to benefit humanity in a way that may otherwise not happen. Compare this to other paths that wealthy people have taken, such as creating trusts that mostly benefit the family and still exist today (e.g. Rockefellers).
Wow, seriously, guys? Is there nobody around anymore who cares about helping the downtrodden of their own good will? Maybe it's naive, but I seriously think there are still some rich people out there who care to use their wealth for purposes other than selfish gratification, and without ulterior motives.
No, no – I didn't mean to suggest that altruism isn't alive and well! My point was that giving is an end unto itself – not a means to establishing a legacy. Also, I just wanted to point out that it takes a LOT of work to manage a big fortune. It's a huge responsibility.