I’m fascinated by a development that has occurred in the last couple of decades: the replacement in numerous contexts, but mostly in journalism, of the simple noun “question” with the noun-phrase “question mark”.
The Spectator supplied a good example when they used the new form in an article on Thursday: “Cain’s departure put a question mark over the future of the others.” What the writer could equally well said was “raises questions over the future of others.” The “question marks” are actually the punctuation we use in print to denote the interrogative. It’s an odd transference from the fact to what might be called the meta-fact.