That's obviously a criticism, but it's currently a big story here in the UK. There's been a lot of vile twitter traffic around this, and someone has been arrested because of it.

This actually tracks into all sorts of privacy issues, and legal issues, and questions of what you can and can't say in media such as twitter (and facebook, etc.)

Do the racist, homophobic rantings of an individual enjoy the protection of "free speech"? When do taunts turn into outright bullying?

These issues have been around for ages, but with Twitter there is the "opportunity" for the pitchfork-toting mobs to get out after people. Where does the right of the individual to speak his/her mind end and the protection of those against whom vitriol is directed begin?