I'm sure there are some commercial applications for Twitter, but they don't really interest me. I mean, 140 characters? I am really not interested in Ashton Kutcher's daily walks. Not for me.
Sentiment: NEGATIVE
One of the interesting things about Twitter is looking how famous people choose to use it. Take someone like Steve Martin, who I follow: it's all sorts of comic gems, nothing private, nothing personal - all jokes. Other celebrities are overtly personal - like Charlie Sheen. I do a mix of observations and updates.