A click-to-donate site is a website where users can click a button to generate a donation for a charity without spending any of their own money.
The money for the donation comes from advertisers whose banners are displayed each time a user clicks the button.
[1][2] While not directly contributing (though many sites offer additional ways of support), visitors are making a difference in the sense that, had they not visited, no donation would have been given.
However, the constriction of online advertising spending around 2001 following the dot-com collapse caused many sites to be closed.
Yet there are still many in operation, notably Freerice,[3] The Hunger Site, and Por Los Chicos.