When you give to Mercy Corps, they follow up with an email that gives you a concrete vision of how you’ve helped. For instance: “Your support of $40 provides a Zimbabwean family clean drinking water for two years.”
Lots of charities have figured out that, in soliciting donations, they need to anchor abstract amounts of money in real-world descriptions (e.g., “Adopt a goat for $60,” “$200 pays for the translation expenses in a human-rights field visit,” etc.). I like how Mercy Corps uses the same principle after the fact. You get the initial satisfaction of giving, and then Mercy Corps follows up and says, effectively, “Thanks for your gift — and, by the way, a Zimbabwean family thanks you, too.” Nicely done.