On Saturday, the Great Firewall of China started blocking YouTube. The apparent cause: Uploads of videos showing protests in Tibete, including this clip from CNN. A YouTube spokesman told Portfolio.com that Google is "looking into the matter, and working to ensure that the service is restored as soon as possible." Details are thin on what Google is actually doing, but Google has made compromises with China in the past. When Google launched its Chinese-language search engine, it stripped out results referring to the Tiananmen Square protests of 1989 and the Falun Gong movement, among other things.