When big news breaks, readers clamor for updates — but they also yearn for context. For example, when word got out Monday afternoon that Jeff Bezos had spent $250 million to become the new owner of The Washington Post, there was suddenly a demand for all kinds of information. Who are the Grahams? How long have they owned the paper? What kind of leader has Bezos been at Amazon? What’s the status of other historic newspapers — have any others been purchased recently?