Philanthropy and charity aren't the same thing. The Gates Foundation does much, much more than just walk around handing out cheques. I'm not even sure they do charity in any significant way, but the money they're putting towards, for example, vaccinating large numbers against the rotavirus, is hugely effective in actually improving things. You can't partake of the global economy when you're shitting yourself to death.
I think they're more alike than different. They have in common the act of giving for the benefit of others. From the Oxford English Dictionary:
Charity. a) Beneficence; liberality to or provision for those in need or distress; alms-giving. b) Money, a gift, or other assistance to relieve need or distress. c) A trust, foundation, organization, etc., for the benefit of those in need or distress; such trusts, etc. viewed collectively.
Philanthropy. Love of human kind; the disposition or effort to promote the happiness and well-being of one's fellow people; practical benevolence.
The difference between the Gates Foundation and other charities is not that it does "philanthropy" rather than "charity"; it's that it operates on a much larger scale and with a greater emphasis on measurement and accountability than do most other charities.
