On Monday, AOL announced in a Facebook post that it was joining the flood of advertisers pulling their spots from the Rush Limbaugh Show. The sponsor defections started last week, when the radio host called Georgetown Law student Sandra Fluke a “slut” and a “prostitute” for testifying before Congress in support of a birth-control mandate. Online outrage eventually boiled over when Limbaugh encouraged Fluke to publish a sex tape. His rationale: If “we are going to pay for your contraceptives and thus pay for you to have sex, we want something. We want you to post the videos online so we can all watch."

The rancor directed at Limbaugh has hardly softened since he posted an apology on his website. At Slate, we’ve been arguing about the role of social media in the corporate backlash against the conservative host. Are Limbaugh’s advertisers deserting him because he pushed the envelope further than he ever had before, or was he felled by a lethal combination of offensiveness, Twitter, and Facebook? Here’s a condensed version of our email exchange.

Torie Bosch: Has anyone rounded up, say, 10 other things Limbaugh did previously that could or should have elicited this level of backlash? As this story emerged, I kept thinking that it didn't seem like he’d crossed a line he hadn’t traversed before.

Farhad Manjoo: Are we seeing something new in social media, with the Komen thing, SOPA, and now this? It seems that Facebook-borne outrage is really doing something.

Hanna Rosin: I am with Torie: I find the outrage of the advertisers perplexing, given all the other awful stuff Limbaugh has said. Paul Farhi did sort of a roundup this morning.

Will Saletan: This is definitely a social media story. Companies and institutions gradually build up motivation to make a change like this, and then somebody produces a handy trigger.

Ben Johnson: +1. In 2012, the only thing that seems to terrify governments, corporations, or celebrities enough to make them act quickly is the fury of the Internet, spread by social media. Can you imagine if there was SOPA-level activism and rage regarding financial reform, spurred by simple, focused messaging? Bank of America was shaking in its boots over the social backlash to its ATM fee hike. The reversals have been kind of jaw-dropping, and they're obviously accelerating.

Daniel Engber: Didn’t the same exact thing happen to Don Imus?  He’d also said lots of outrageous things, but his racist comments in 2007 lost him all his sponsors and got him exiled to satellite radio. Back then, tiny Facebook wasn’t even making a profit. Or was that a social media story that played out on Friendster?

Bill Smee: I’m completely with Engber here. Rush Limbaugh outrage and consequent sponsorship desertion would have happened with or without social media furor. Twitter and Facebook probably just accelerated the reaction.

Bosch: I'm still puzzling over why this was the big one for Limbaugh. What made it different? The fact that Obama got involved by calling Fluke?

Manjoo: Maybe because it was directed at a specific person? A college student, not a politician or pundit. Sort of like how Imus insulted the Rutgers women’s basketball team. 

Lithwick: It was a private person. And instead of apologizing—like David Letterman did after joking about Bristol Palin getting knocked up by Alex Rodriguez—Limbaugh dialed it up and asked for a sex tape.

Jeremy Stahl: I disagree. Jack Shafer had a great tweet on this over the weekend: “Is this Limbaugh's Imus moment? His enemies leveraging public opinion to send him into exile for what he's done in the open for decades?” Had Rush said the same exact thing as Imus pre-social media, he would have been fine. One could argue that he has said the equivalent or worse to what he said about Fluke for years and hasn’t suffered any consequences until now. Twitter and Facebook make it really easy to put pressure on corporate sponsors in a way that was a lot more complicated to organize just a few years ago.

Engber: There's an attribution bias here. Twitter and Facebook are buzzing about all sorts of things, every day of the week.  Whenever one of those things has real consequences, we want to trace it backwards to Twitter and Facebook.  But what about the zillions of trending topics that don't go anywhere?

Dan Check: This is basically the shock jock black swan. Being terribly offensive works great until it doesn’t. Even though you're just doing what you always did to the people you always did it to, you're going to run into trouble.

Rachael Levy: Maybe it’s just the fact that among the many words in Limbaugh’s tirade, he said "slut." That was a big eye-catcher in the headlines.

Rachael Larimore: If that were the case, Bill Maher would have gotten more crap for calling Palin a cunt.

Manjoo: But there's the private person distinction. Maybe it's become acceptable to call public people whatever you want. It's still not OK to do that with a college student.