I just learned about the horrible terrorist attacks in Mumbai. I've been following the developments on Twitter - weird how just a few months ago I would have immediately turned on the TV and set it on CNN. Another good example of the effectiveness of social media in times of crises.
Poynter has a good summary of all the social media sites currently covering this tragedy.
11/27: CNN and Gauravonomics also have detailed accounts of the real time citizen journalism that took place during the attacks.