A crash course in changing the world.
Ushahidi is a very useful application that can allow people in the surrounding area about potential problems in the area. I believe a good way to warn the public about issues in the United States is using the iPhone idea with Amber Alerts. Currently, Apple has a system where if you are in a certain area where the Amber Alert is issued, you automatically get a message on your iPhone. This idea could be utilized with natural disasters etc. and applied to multiple different devices, not just Apple. Nowadays everyone has a cellphone and checks it regularly.