Peer Pressure Works on Billionaires Too

There's nothing like a little prodding from Bill Gates and Warren Buffett to get rich people to part with their money -- or half of it, at least. The pair has convinced over 30 of their fellow billionaires (and a handful of other millionaires) to sign the Giving Pledge, described on the pledge's website as "an effort to help address society's most pressing problems by inviting the wealthiest American families and individuals to commit to giving more than half of their wealth to philanthropy...