To talk about philanthropy is to talk about that great action of helping someone who really needs it without expecting something back, to help just for the love of doing it and for the satisfaction that you feel when someone says "thank you" and they really mean it, to see how happy they are when you help them.
Philanthropists can contribute to so many causes, from saving the planet making people aware about global warming, like former vicepresident Al Gore, to raise money to build hospitals and new homes for earthquake victims in Haiti, and you named it, where there's a problem there are people trying to help.
Philanthropy may be the biggest gesture of love from one being to another because it shows solidarity, support and being one hell of a good person. Philantropy's good sides may be that personal reward you feel when you help someone in need, to put some of you to build a better and more loving community, and hey, why not a better world?
I can not see a disadvantage for philanthropy, even if some companies or people do it just for evading taxes, who cares? They do raise awareness among people and I think they do give some part of the fundraised to the real cause.
So, philanthropy is love to others translated in good actions, and if you want to be one, you don't really need to have a lot of money, just the intention to help and actually do it, so come on, what are you waiting fot to change your world?