Cardmembers can submit project ideas for making the world better. For every cardmember that registers (with a project or not), AmEx will donate $1 towards the winning idea, up to a max of $5 million dollars. So, if only 4 million people register, the project only gets $4 million.
After you register, you can discuss and rate the projects that have been submitted. A note I saw from an AmEx publicist said that the company was "overwhelmed" with the number of projects they've received related to energy and the environment.
A lot of the projects I've looked through so far seem more like generic ideas and rants ("CFLs good," "It's easy: plant a tree," sort of thing) than well-thought out proposals But there are some interesting and more specific projects too, like using the award money to make the city of Galesburg, IL energy-efficient and "greener," or a summer camp for kids to learn about energy challenges and solutions.
The deadline for registering projects and for rating them is Sunday, June 17th. The top 50 projects will be announced on July 3rd. Cardmembers will vote and chose the winner, which will be announced August 7.