The more I think about it, the more I don't know.
On the one hand, I feel like leaderboards go against the spirit of charity, in that they're acts of sacrifice made with humility and discretion, done for the importance of the deed and not for the importance of recognition. At the same time, what might be a big offering by one person could easily be over shadowed by a small offering from someone else. For example, if Mr. James and his third grade class had a bake sale and raised a hundred dollars, that's a pretty significant act that would easily be overshadowed by say, a millionaire who decides to donate 10k. The kids worked hard and if any recognition should be doled out, they deserve it, but they can't compete against someone who could sneeze out some cash and not even worry.
But on the other hand, I can see how leaderboards could be great motivators. If someone loves recognition so much that they're willing to pay big for it, that's a win for the charity. Likewise, if someone is falling far short of their potential, they could face a bit of shame and derision. Also, sometimes some friendly competition doesn't hurt. But then again, giving is about understanding the need, not for love of fame or fear of guilt.