You can get real specific after the event, it's 20-20.
But a previous post of mine where I cited the Wikipedia article on the Maid of Lorraine prophecies proved it was real specific before the event.
I think what he meant was, it's pretty easy to fit a past event to some supposed prophecy, but it's not as easy to do the same when the supposed event hasn't happened yet. I'll go back to Nostradamus again...there's been books by commentators, people who were trying to convince the readers that Nostradamus really knew the future. They often made some fairly convincing applications of his predictions to things that had already happened. BUT, when they tried to say what he had predicted was still to come, they typically failed, in sometimes comically bad fashion.