Via Idealware's blog, I found an interesting Green Media Toolshed writeup of using Google Earth for advocacy:

Appalachian Voices is using Google Earth to shine the light on the destruction of mountains through mountain top removal. This is a great tool because it can help you reach out to audiences you may not have reached before. We are happy to see one of our members using a tool like this for their advocacy work. It is a great example of how powerful online tools can be and we hope that other progressives take note.

Go to ilovemountains.org to learn more about the tool.