Nate Silver made a rather good analysis of his own failings with respect to the primary: http://fivethirtyeight.com/features/how-i-acted-like-a-pundi....

I agree substantially more with his own analysis than I do with this blog post. He even mentions that the introspection may have gone too far. Why is it that Trump's victory has been seen as a "another failure of the pollsters"? Fivethiryeight had him at 35% chance. Betting markets were at around 4.1 the day before IIRC. In my view it's just another narrative to sell to people - laughing at other "stupid" people, here, read our newspaper instead.