We don't have this SOPA thing in the UK (for obvious reasons) but there are numerous laws like it, and they have distinct and detrimental effects onthe way people interact with each other. When you can face jail for innocent actions that are only illegal because someone doesn't like them, you tend to be wary of who you talk to and what you say. It takes away your freedom to speak.
SOPA, and its Senate counterpart PIPA, using the excuse of media "piracy", are a thinly veiled attempt to control the flow of information on the internet. They threaten both the free speech rights of internet uses and their technical security - they powers demanded by these bills will break current attempts to increase the security of DNS requests and won't stop any of the things they claim to prevent.
When the state attempts to limit your access to information it is taking away your freedom; not only your right to free speech, but your ability to make informed decisions and to listen to opposing ideas will be taken away as well.






