That may be technically correct. But Facebook trademarking "BOOK" is just stupid, on its face. Also, I note that "facebook" itself was a term that had been use

That may be technically correct. But Facebook trademarking "BOOK" is just stupid, on its face. Also, I note that "facebook" itself was a term that had been used by universities for years to describe books of students' faces. As by Harvard, which Facebook was riffing on. Maybe it's OK to allow such trademarks. But there ought to be restrictions on holders suing over currently typical usage.