Last October the Scientific American published an eye-opening article on how the FDA manipulates the media with something called a close-hold embargo. Make sure you check out that article.
You'll see how government agencies, large corporations and even non-profit orgs consistently manage the media and control the messages that get out into public consumption.
As media consumers, we need to be on the lookout for this kind of colluded secrecy. One way to monitor how this works is to set up an RSS feed on some kind of service like Feedly and take notice when a group of mainstream press outlets publish the same story all at once - and one of the major media outlets is conspicously missing.
Here's more general information on press embargoes and how they work. Also, more fallout from the Scientific American expose from Business Insider.