10 years ago, Spocko, the blogger who runs Spocko’s Brain, started to send records to advertisers showing what hate-talk radio jocks were showing immediately before and after these ads.

He asked a simple question: Do you really want your products associated with this?

It now appears that it has dawned on online activists that they can do the same thing with online news.

It’s even easier, you just have to email a screen shot with their ad and a headline:

One day in late November, an earth and environmental science professor named Nathan Phillips visited Breitbart News for the first time. Mr. Phillips had heard about the hateful headlines on the site — like “Birth Control Makes Women Unattractive and Crazy” — and wondered what kind of companies would support such messages with their ad dollars. When he clicked on the site, he was shocked to discover ads for universities, including one for the graduate school where he’d received his own degree — Duke University’s Nicholas School of the Environment. “That was a punch in the stomach,” he said.

Why would an environmental science program want to be promoted on a site that denies the existence of climate change? Mr. Phillips figured — correctly — that Duke officials did not know where their ads were appearing, so he sent a tweet to Duke about its association with the “sexist racist” site. Eventually, after a flurry of communication with the environment department, he received a satisfying resolution — an assurance that its ads would no longer show up on Breitbart.

………

In mid-November, a Twitter group called Sleeping Giants became the hub of the new movement. The Giants and their followers have communicated with more than 1,000 companies and nonprofit groups whose ads appeared on Breitbart, and about 400 of those organizations have promised to remove the site from future ad buys.

“We’re focused on Breitbart News right now because they’re the biggest fish,” a founder of Sleeping Giants told me. (He requested anonymity because some members of the group work in the digital-media industry.) Eventually, Sleeping Giants would like to broaden its campaign to take on a menagerie of bad actors, but that would require a much bigger army of Giants, and “it has only been a month since we started doing this,” he told me when I talked to him in December. Then he added, “This has been the longest month of my life.”

Advertisers have been fleeing Rush Limbaugh’s show for precisely the same reason ever since he tried to slut shame Sandra Fluke, and it appears from the silence over the numbers, last time around they were trumpeting the numbers, that he took a significant pay cut.

Everyone has a right to free speech, but that doesn’t mean that they have a right for you to support their sponsors.