I had the pleasure of meeting the people behind Knowmore.org, the nonprofit that let's you vote with your wallet. Knowmore developed a Firefox extension that lets consumers make better choices about the products they purchase. By exposing corporate abuse, knowmore.org empowers individuals to make a difference by changing the way they choose to spend their money.
What's interesting about this approach is that it creates a virtual community of consumers using relatively simple technology (easy for me to say that--I can't write code). But you get the idea. You can watch the video of Tom Inhaler, to learn more about Knowmore.org.
If you want to join the community, you can download the Knowmore Firefox extension here.