Please take a look at this video about a successful campaign waged by a group of young activists in Chile called Chao Pescao against the Barrancones coal plant. They made a video and started a social media campaign that went viral, got lots of celebrities involved, and galvanized a national movement that resulted in the plant being canceled by the Chilean President back in 2010. And they did all of this on virtually no budget! Chao Pescao are brilliant at communications and I think could teach us all a lot about how to develop these sorts of communications campaigns. The video is only 5 minutes long, and well worth a watch.
For more information, you can watch a one hour documentary.