Today marks the day that sites like Google and Wikipedia will show what the internet might look like if Draconian laws are passed to stop infringement. Such laws would require constant vigilance, patrolling for whatever the government defines as illegal and silencing it before the government takes down your site. Under the auspice of copyright infringement, it could easy grow into policies similar to North Korea or China where unpopular ideas would simple vanish under the crushing weight of the law.
If you want to learn more, I suggest Wikipedia. While it's main site is down in protest, This link is available to explain why.