Take this with a grain of salt, I heard it on MSNBC just after Dzhokhar Tsarnaev was captured. There was a gunfight in a neighborhood, and obviously everyone in the neighborhood was tense and attentive. At some point after a volley of shots, the police *posted* (I suppose they had a Twitter account?) that the suspect was in custody. The reporter said that you could hear applause coming from various parts of the neighborhood. (No tweets from Dzokhar, he was bleeding).
This was the most social-mediated manhunt ever.