Whenever a friend asks for a donation for their marathon or mustache charity, I always give them some small amount of cash. And in the course of donating this cash via credit card, I'm required to give my mailing address. Almost every single one of those charities now solicits me for more money by sending me information in the mail. With my limited knowledge of the costs associated with direct mail marketing, I estimate that almost half of my donations have ended up unprofitable for the organizations since I never send them anymore cash. These charities really ought to have a check box on the donation form that says, "I'm only giving this money for my friend and don't even know what your charity does, please don't solicit future donations."