Forty of America’s richest families have committed to the Giving Pledge, an effort by Bill and Melinda Gates and Warren Buffett have recently contacted between 70 and 80 American billionaires in the last 6 weeks to commit to a Giving Pledge to donate at least half their money to charity. Their success rate to date has been about 50 percent, and they will be meeting with some of China’s and India’s wealthiest people in late September 2010 and March 2011.

Among the forty of America’s richest families are New York Mayor Michael R. Bloomberg; eBay founder Pierre Omidyar and his wife, Pam; CNN founder Ted Turner; energy investor John Arnold and his wife Laural media executive Barry Diller and his wife; designer Diane von Furstenberg; investor Ronald O. Perelman; businessman George B. Kaiser; financier Kenneth G. Langone; and Oracle founder Larry Ellison.

The Gateses and Mr. Buffett have asked Giving Pledge members to write a letter describing their thinking on philanthropy as an example to others, published on http://givingpledge.org

Forbes magazine estimates the net worth of donors who have so far committed to giving away a share of their wealth totals more than $200-billion.