There is a problem with The Hunger Site, The Rainforest Site, and the various other spinoffs. When you click the
give food button, you are in effect taking some money from the Christian Children's Fund,
World Vision and a few sites selling
fair trade style products, and giving the same amount of money to Mercy Corps and
America's Second Harvest to be distributed. When you click the button, World Vision sends Mercy Corps some money in return for showing you some adverts. Unless you actually buy something advertised, you are merely moving money from one group of charities to another. This seems distinctly pointless, unless you hold Mercy Core in much higher regard than the other charities. Personally, I would feel far more
justified in clicking daily if the adverts providing the money were from
Starbucks.
Clicking might make you feel good, depending on whether you agree with the above or not, but it does not seem to benefit the world as a whole, in any direct way.