To start, here is David French on the threats he and his wife get daily because he was against Trump. I guess a specialty of some alt-right creeps is to Photoshop his wife's face onto the most disgusting pornographic image they can find and then send her the resulting artwork.
Next, it was instructive to read what Breitbart had to say about the alt-right. Basically, they are currently noisy frat boys, but they're also right:
"In short, they want what every people fighting for self-determination in history have ever wanted, ... — to come out of the woodwork and stand up for their values and culture."
This at the end of an article about the white nationalism, xenophobia, misogyny, and hate in the movement.
A related question is how much Steve Bannon, Trump's chief strategist and adviser, is a fellow of the alt-right. Ben Shapiro, formerly of Breitbart and thus a colleague of Steve Bannon, drops a lot of stories on him. The charges seem fairly specific, but I can't be an unbiased judge.
However, the press isn't finding very horrendous quotes attached to Bannon. Maybe this will change because he had a radio show, and people may need to listen to a lot of it to find the nastiest bits. Stay tuned.
Update 2/21/17. Milo Yiannopoulos, author of that article in Breitbart about the alt-right, was invited and then disinvited from this year's CPAC conference. He's been a popular guest on college campuses, invited by conservative groups because he infuriates liberals. But evidently he went too far in talking about sex with underage teens, so his fame and welcome are drying up extremely quickly. Ah, a bit of justice.
Update 3/14/17. I don't generally read The Daily Kos, but this very long article has a surprising number of well-made points, with many links. Not your typical conspiracy theory.