Freedom of access to information is part of our professional ethics:
Librarians and other information workers reject the denial and restriction of access to information and ideas most particularly through censorship whether by states, governments, or religious or civil society institutions. (IFLA Code of Ethics, also endorsed by ALIA)
So here is an important element to that debate:
Whilst the discussion of the legal issues are US centric, there are useful descriptions of what is happening in the internet space from some of the big players and why we as information professionals should care.
CEO and State Librarian
State Library of Western Australia