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.
Sadly, whites are rarely open to what black and brown folks have to say regarding their ongoing experiences with racist mistreatment. And we are especially reluctant to discuss what that mistreatment means for us as whites: namely that we end up with more and better opportunities as the flipside of discrimination.