Making threatening statements against anyone should be taken seriously. It does not matter if the threats were made as a joke, or to make an example; if the threats are serious enough they should warrant jail time. A better way of raising awareness about racial issues is to create a dialogue with other students. In short, depending on how serious the threats were, the student that made them may deserve jail time.
Black students who tweeted threats to other black students for the purpose of raising awareness about racial issues should receive jail time. At a time when the nation is on heightened alert after several high profile incidents, it is particularly egregious that people would falsely try to stir up the pot.
If his mission was to raise awareness about racial issues, and he had no intent to actually harm anyone, then I don't believe he deserves jail time. It was probably an rather stupid idea, and could've been handled differently, but is not worthy of spending time in jail. I feel that he has probably already learned his error, and won't make the same mistake again.
He should not receive jail time. The punishment must fit the crime. Society must understand that while social media is a powerful communication tool, it is just that -- a tool. Most young people tweet or use some form of social media to discuss their issues with peers. Often, it is a way to let off steam, or just to connect. Teens may say things they don't mean in the heat of the moment. Adults do it too. There is always room for apologies. However, as in many other instances, it is a crime to utter threats or to stalk people online. Online child predators have been tracked and arrested. Usually, they are older men preying on innocent teenage girls. Police can find these predators, and punish them depending on the severity of the online stalking. Parents need to gather at PTA meetings, and decide how to deal with the issue. If the threats are harsh, and the teen acted upon them, the teen will likely be suspended from school and sent to a detention centre.