Paul Farhi reports for The Washington Post:

Hardly anyone paid attention last November when a strangely named Twitter account, Sleeping Giants, sent its first tweet into the digisphere. “Are you aware that you’re advertising on Breitbart, the alt-right’s biggest champion, today?” read the tweet, aimed at a consumer lending outfit called Social Finance. “Are you supporting them publicly?”

Within 30 minutes, Social Finance replied, tweeting that it would stop running ads on Breitbart.

It was, it turns out, the start of an odd, and oddly effective, social media campaign against Breitbart.com, the influential conservative news site headed by Stephen Bannon, President Trump’s former campaign chairman and ex-White House chief strategist.

Sleeping Giants is a mysterious group that has no address, no organizational structure and no officers. At least none that are publicly known. All of its leaders are anonymous, and much of what it claims is difficult to independently verify. A spokesman for the group wouldn’t identify himself in interviews for this story.

But the group does have a singular purpose, pursued as relentlessly as Ahab chasing a whale: It aims to drive advertisers away from Breitbart. “We’re trying to defund bigotry,” the spokesman says.