Controlling the Web 2.0

Why is the outcome of the Tienanmen protests of 1989 so different from that of the mourning following the 2008 Sichuan earthquake? Clay Shirky in his TED talk in 2009 describes the immediate response of Chinese citizens to the massive quake. Even before official geological institutions could verify and report on the event, people were talking about the destruction on Twitter. He mentions a past earthquake and the Chinese government's response to it: they failed to acknowledge it for three months, and for 'good' reason. If you're a controlling communist government bent on maintaining your nation's image, why announce to the world the kind of destruction that probably ensued such a catastrophic event? It's clear that the same thing was probably desired for the 2008 quake, but not possible. The different response to the protests that followed is what is intriguing. In 1989, over 100 protesters were killed and 7,000 injured. Although there was an apparent out lash against protesters in 2008, why was the final outcome so drastically different?