Last Monday night, Mike Mitchell, a 27-year-old freelance artist living in Los Angeles, tweeted a link to a poster he created in support of Conan O’Brien. The poster—which has become the official face of “I’m with COCO,” the quasi-official campaign in support of Conan O’Brien against NBC’s decision to restore Jay Leno to the nightly 11:35 slot—bears more than a passing resemblance to Shepard Fairey’s iconic image of Barack Obama.

I recently spoke with Mitchell about the viral image that he created. “I woke up the next day and it was crazy,” Mitchell said, “I was getting contacted by all of these media outlets and being flooded.” In a matter of days, countless people, including Conan’s staff, started using the image as their avatars. Mitchell doesn’t know how it spread so fast.

As it turns out, the “I’m with COCO” image was promptly picked up by another Conan supporter who created the “I’m with COCO” fan page on Facebook. (Mitchell was then added as an admin.) The “I’m with COCO” page—which facetiously, albeit plausibly, describes itself as a “Religious Organization”—has garnered over 250,000 supporters in the past week, far outpacing anything in the Leno camp. If you were to hit “Refresh” on your browser any night last week, you’d likely see the number of COCO fans increasing by 20-30 in a matter of seconds. Over on Twitter, the web’s other bellwether of now, data compiled by Trendrr and featured in Advertising Age showed that chatter and sentiment on the site leaned heavily in favor of Conan from January 9th to January 16th.

That Conan would appear to be more popular on social media sites is not surprising given that these sites are more popular with young people and Leno’s audience tends to be older. What is surprising, if not perplexing, is that NBC has chosen the older demographic over the one traditionally favored by advertisers. (That’s still how television networks are supposed to make money, right?) Fox, which employed Conan O’Brien as a writer for “The Simpsons” and may be courting him again, must be toasting right now to the NBC debacle.

History repeats itself, sort of. Back in 1992, NBC’s decision to tap Jay Leno, and not David Letterman, to fill Johnny Carson’s coveted chair reminds us that the network is no stranger to “Tonight Show” drama. The difference between then and now, however, is that the audience is not a faceless Nielsen rating: it’s connected, vocal, and in typical web fashion, very opinionated.

The online campaign for Conan will not reverse the decision of NBC executives. Still, moving forward, it will probably cause the big networks to think more carefully about how their audiences might respond—especially when that audience is armed with social media—before making big decisions. I asked Mike Mitchell what he saw as the goal of the “I’m with COCO” movement, which has moved from the internet to staging ‘rallies’ in various cities, and he offered a humble response, “I’d like NBC to look at it and maybe think that they’ve made a mistake.”