How to run a social change campaign

Here is an example of how to organize a crowd around an issue.  The old sign-the-petition campaign comes to twitter and is helped by this simple yet very appealing site: Outlook’s broken—Let’s fix it.  The background is reminiscent of the display Apple used at this year's WWDC to show the success of the iPhone App Store.  (watch the video to get the full effect).   Sure makes visitors feel as though they are part of a larger movement.