I admire how all the agencies are working together to protest a cause. However, I really don't like how they chose to do so. First of all, as rajat mentioned (http://news.ycombinator.com/item?id=1128286) why use flash? Not only is it slower to load than an image such as a png, but what about those browser's/phones (ahhem the iPhone) that don't have flash capabilities?
I attempted to read the messages on each site, but many times I would get connection timeouts as I jumped from site to site, which became annoying after a while so I stopped even trying to continue reading.
With that said I don't think it's very effective. I think a better way would have been to buy a domain and have all the websites protesting forward to it and show the protest message there.