Looks as though Bill Gates' billionaire challenge is paying off: Microsoft co-founder Paul Allen has pledged to give away most of his $13 billion fortune. He made the vow public a month after Bill and Melinda Gates and Warren Buffett urged the world's richest to give away at least half of their wealth. Allen, the 37th-richest person in the world on the most recent Forbes list, hopes to "spur other people to give," a rep tells the Seattle Times.
Though he has not previously spoken out on philanthropy, Allen is no stranger to giving, notes the Wall Street Journal. The Seattle native has already given away about $1 billion, primarily in the Pacific Northwest. His new philanthropic effort will keep that same focus and add projects with an international scope, said his rep. (Read more Paul Allen stories.)