August 4, 2010; Source: msnbc.com | Remember the Buffett challenge to get billionaires to give away half of their wealth? The investment genius from Omaha along with that computer-oriented piker from Seattle, Bill Gates, now have 40 billionaires who have signed onto this campaign, with letters expressing their charitable intent posted at givingpledge.org.

Buffett and Gates started buttonholing their rich and famous (or not so famous) peers from the Forbes 400 and ended up calling 70 to get 40, though they don’t plan to stop. The list, however, seems heavily weighted to billionaires who have already established big foundations and seemed well on their way to pledging billions to philanthropic institutions that they controlled. Some of the names on the list are well known in foundation circles, though billionaire philanthropy need not end up buried in foundation endowments.

Among them: in California, Eli and Edythe Broad (with an eponymous foundation), Ann and John Doerr (he the Silicon Valley hedge fund guy who is putting money behind the Social Innovation Fund Doerr also gave $1 million to the private prep school which the his daughter attended), Tashia and John Morgridge (Cisco Systems money), Herb and Marion Sandler (the former Golden West bank owners who are bankrolling ProPublica), Jeff Skoll (of the movies and the social entrepreneurship-oriented Skoll Foundation); in Hawai’i, Pam and Pierre Omidyar (eBay money and the Omidyar Foundation, like Skoll and Doerr focused on social entrepreneurship); in the state of Washington, Paul Allen of Microsoft keeping up with the Gateses; in New York, Mayor Michael Bloomberg, Joan and Sanford Weill (Weill was the chair of Citicorp and, in philanthropic circles infamous for using a $1 million Citi grant to the 92nd Street Y so that a Solomon Smith Barney guy who worked for Weill could get his kids into the tony preschool); and from Texas, T. Boone Pickens (recently the visionary natural gas-as-a-substitute-for-Mideast-oil promoter, but long known as a philanthropist who pulled some unusual stunts with gifts to Oklahoma State University sports and support for political causes such as the Swift Boat Veterans ). (Find the list of all 40 here).

This trend has potential up and downsides—NPQ will be covering this story with analysis on its front page.—Rick Cohen