Actually, a while ago, I was thinking about something like this as well.
Like a website where people from all over the world could come and join forces and help charities. Also, everyone has different connections that could help certain charities.
I was thinking of something a bit like
Sourceforge for those who know that, but for charities.
Charities could then post pictures of the results of the donations they receive, and could really give people the option to donate for specific things. So that people really know where their money is going.
I think a lot of people would be much more willing to donate if they specifically know where their money is going and could maybe even see pictures of the causes they're helping. This could both be for local projects or projects far away.