David sez, "On a decentralized network it's much harder to map blockages than to create them. Herdict.org takes a crowdsourcing approach. Install the add-on and click the button when you encounter a site that's down. Herdict aggregates this information, including your geographic location, to draw a map of the Internet's potholes, including the ones intentionally dug by frightened governments. If you have a few spare minutes, you can check sites others have reported as down, determining whether they're blocked in your part of the world as well. (www.AmIBlockedOrNot.org will take you to that part of the Herdict site.) Herdict is a project of Harvard's Berkman Center (sponsored by Jonathan Zittrain) and obeys all the appropriate privacy rules of the road."