Here's an interesting "virtual march" by TheBigAsk.com, an appeal to the grassroots to promote climate change legislation amongst their elected representatives. The campaign allows people to upload their own video of their appeal, they make pinkynail images to create a mosaic that's fun to poke around in, exploring people's use of the site. There's always a call to action and the "friction" to forward or contribute is almost nil. Dig it. http://www.thebigask.com