Anwar al-Awlaki is an American born Cleric who is now hiding in Yemen. He recently uploaded anti-American videos to Youtube and when congress asked Youtube to remove them, Youtube obliged.
However, if you now search, you can still find many videos on Youtube by Mr. Awlaki. Congress is hesitant to pass any law banning these videos as it will probably be a violation of the 1st Amendment.
What is interesting here is that Youtube, a popular social media site, is being used to propagate anti-American ideals. It is being used as a platform to spread these ideas when, most likely, no other source available to United States Muslims (his target audience) would allow Mr. Awlaki airtime.
In our discussion of media and politics, we need to also analyze other news sources, like Youtube, which allow anybody with internet access to reach a worldwide audience. Never in human history has it been so easy to reach so many people, so fast. Even 15 years ago, only the most powerful and rich could reach millions. This power was reserved for CEO's, governments and newspapers. Now, anyone can post something that can be accessible by billions of people.
Congress is concerned with Youtube because these mediums have sway in the political arena.