Some amount of credit for the win must be directed at the digital operation, which was profiled at length in Bloomberg Businessweek.

An alarming, but unsurprising, statement made in that profile:

“We have three major voter suppression operations under way,” says a senior official. They’re aimed at three groups Clinton needs to win overwhelmingly: idealistic white liberals, young women, and African Americans.

Some of the tactics used to drive this suppression have recently been reported, including the use of "Dark Posts" via Facebook Ads:

For example, Trump’s digital team created a South Park-style animation of Hillary Clinton delivering the “super predator” line (using audio from her original 1996 sound bite), as cartoon text popped up around her: “Hillary Thinks African Americans are Super Predators.” Then, Trump’s animated “super predator” political advertisement was delivered to certain African American voters via Facebook “dark posts” — nonpublic paid posts shown only to the Facebook users that Trump chose.

Many people are susceptible to believing anything they see on Facebook or Google. The idea that anything could be loaded into a Dark Post and receive massive, targeted distribution via Facebook Ads without broad public scrutiny is alarming.