I've said it before, a boycot simply will never work on the scale you are talking about. First off, we will be unlikely to impact any of those mega rich corps enough to cause any grief. There are still millions of people who will still watch the tv and continue to buy what they want when they want. Secondly, assuming we did cause a company or 2, or more, to drop advertising on that particular channel, it still wouldn't work. Most of us here believe in the free market, and how that works is the MSM would need to sell those valuable primetime ad slots, and would lower the price to entice new customers. There is the very real possibility the rates wouldn't change, just the advertisers.
Lastly, its not the advertisers direct fault that the MSM is so biased and corrupt. They are companies trying to sell a product, I love CHEVY trucks, so ill keep buying those trucks as long as I can afford them. We need to go after the actual anchors, and generate negative publicity towards them. Find out where they live, organize demonstrations, plaster youtube videos everywhere you can. This can only work if there is an organized and dedicated operation in place.
I don't think its worth the energy. They will always be in power, and to truly win means we have to continue winning people over to our cause any way we can. Keep spreading the message, don't let the media get you down.