David Graeber is - still - an anthropology prof at Yale. His contract was not renewed (i.e. he was fired), but has been allowed to continue working for a year while he interviews for new positions. Many people, including David, suspect the firing was because of David's political leanings - David is an anarchist (great Wiki page. so that's who all those kids are at the protests - the kids dressed in black).
This article gives the background.
Clamor magazine looks at the bigger issue of freedom of speech on campus (link from Political Theory Daily Review):
Can anyone explain the sudden free speech frenzy at America’s colleges and universities? At the University of Colorado at Boulder, a radical professor’s scholarship and ethnicity is the subject of an official review. Yale fired an anarchist professor and refuses to explain why. Some conservatives are calling for an end to tenure and others want to use the legislature to write codes of conduct for professors and their students. Are these items part of a conservative thrust to squelch dissent on campus? Answer and explain your reasoning in 500 words or less.
Sign the online petition, yo.