This is a pretty open-ended question, can be about politics, business, technology, culture, most things really. Only requirement is that what you thought was gonna happen actually happened because obviously there is a lot of stuff that will happen in the future if problems keep being dismissed by dumb people.
If my title is not clear, someone claiming letting social media be run by the same ads that run television is a recipe for disaster in 2010 is someone ahead of the curve (by a lot, obviously).
In my case, a teacher once asked me to write a satire paper/ficticious news article or something, I wrote about anti-democracy protests in Brazil. 2-3 years later, there were anti democracy protests, although most of the details were either missed or wrong.