Here's something interesting:
With the continued rise of Web 2.0 and user-generated content, filtering/blocking access to that material by repressive regimes has become another hotspot on the censorship battleground. The Global Voices Advocacy group have a story about it here.
The group have also created an interactive Google map that points to the countries where this form censorship exists and the Web 2.0 sites that are blocked in those countries. The map also indicates locations where citizens and activist groups are speaking out against filtering/blocking user-generated content.