There's an old bumper sticker that reads "If you're not angry, you're not paying attention." While I agree with the sentiment, the underlying assumption is that if you pay attention, you'll know what's happening. But this isn't always true: although information wants to be free, it's usually the case that there are some entities which benefit from preventing the dissemination of the information, and if those entities have enough power, you might not know what's happening, even if you're paying attention. Fortunately, there are organizations that fight such efforts to restrict the free flow of information. One of them is Project Censored, which compiles an annual list of the top socially significant news stories that they feel are being underreported or self-censored by the mainstream media in the U.S. Here's the latest list.
http://www.projectcensored.org/censored_2007/index.htm