Upvoted for calculation. Shakes fist for arguing against my pet cause. Although I didn't do the math, I suspected that it might turn out this way. I didn't mention that because of a chain of thought similar to grouchymusicologist's. I figure that people will not disrupt their money-earning time to sign up for this and for that reason donate less to charity. I think it's far more likely that they will be fooling around on the internet, reading LessWrong, and might feel motivated to use some time that would otherwise be spent unproductively on signing up. I hoped that the easy fuzzies might motivate some people into an act of "charity" that they otherwise might not make.