I think they hit the nail on the head when they let people make donations via text message. People like feeling good about giving to charity, but they’re usually too lazy to find a charity, do research and then take the credit card to make a donation. So sending a one or two word text message is about as little effort you can exert in order to donate to charity.

That said, I think Sprite wasn’t in on the meeting where they mentioned that doing anything else is probably not going to be nearly as successful, especially when the postage would cost more than the donation resulting from it. Obviously it’d be smarter to amass soda tabs but you’d have to be drinking A LOT of Sprite to get an appreciable amount so even then it still won’t be that efficient.