I suspected this could happen. The writing's been on the wall and for those who are shock need to desperately reevaluate their understanding of the country and world we live in:
1) Clinton is a bad, unlikeable candidate. She's lost every real election she's attempted. New York Senator is a celebrity glamour position, not a real grassroots election. She went from frontrunner against Obama to getting crushed by him. She could barely fend off a socialist in the primary that was rigged in her favor from the beginning. Every step of the way, Dems were looking elsewhere - Biden, etc. She was a problem candidate from the beginning and suffered from a lack of competition.
2) On the flipside, Trump was a joke in the beginning and kept gather converts. He kept over performing. He nailed two big issues: immigration and the assault on political correctness. He didn't really trip up because he never came across as a hypocrite. All of his gaffes were consistent with what we expected of him. And his supporters were passionate in the way Obama, Bill Clinton, and GW supporters were passionate.
3) The Breexit was a warning shot that ordinary folks are deeply disillusioned with the progressive, urban, global vision of free trade, liberal immigration, environmentalism, diversity, etc, epitomized by institutions like the UN, Davos, TED, Aspen ideas, etc.
I urge people to not despair. This is democracy in action. The result may not be to our taste, but it's a pretty amazing f--- you to the political and media power structure who all thought it unfathomable Trump could win. And that's kinda cool and how it's supposed to work. It is a reckoning for the outrageous level of arrogance amongst coastal elites and should be read as a humbling reevaluation of certain sacred principals such as non-enforcement of immigration, identity politics, and thought-police levels of political correctness.
I want to add two final notes: I do not believe this is about tacit or overt racism or "hate" as you will hear people say for the next weeks, or perhaps years. There is demographic anxiety about the future of American culture and we need a new language to discuss these issues without calling it racism, which it is not. The concept of enforcing and limiting illegal immigration is not an inherently racist idea. Nor is wearing halloween costumes. Enough already. 56 million Americans are not racists and nor is Donald Trump.
538 and other pollsters were giving Hillary between 75-95% chance of winning. Now, I ask...what is more impressive - 538 picking the 2008 election breakdown right (which is really like going 8 for 8), or Public Musings predicting Trump? I'd argue Trump. I guess my point is that "data analysis" is good for telling us predictable information, but much less able to tell us unpredictable information. In short, it tells us the information least worth knowing.
UPDATE: One other tea leaf -- the tea party movement. It was dismissed and mocked by the coastal elites. This was a movement centered around the idea that government's gotten too big and unwieldy. Nothing particularly controversial. It was a popular, civil form of protest not taken seriously and Trump is the reaction.