On June 28, 1914, Archduke Franz Ferdinand was assassinated in Sarajevo. One month later, Austria-Hungary declared war on Serbia, to which Russia responded by declaring war on Austria-Hungary, forcing its allies France and Great Britain into the war. In the aftermath, Germany honoured its defensive pact with Austria-Hungary and declared war on France, plunging Europe in a chaos that nobody had predicted.

Cliodynamics, the mathematical approach to History, still has a long way to go to reach the accuracy of Isaac Asimov’s fictive psychohistory. Its closest non science-fiction relative, culturomics, relies on the idea that historical trends are accessible through the digital literature. As Jean-Baptiste Michel explains on TED, the course of History leaves a strong mark on the things we write about, and on the way we write about them.

But historical events are not the only thing we write about. The digital records are mostly about anything we find interesting. Knowing what is talked about is not science-fiction, it is actually fairly easy. More challenging is to know whether a topic is currently on the rise or merely fluctuating, which is a changepoint detection problem. Research on changepoint problems...