Twentysomethings could care less about television, particularly late night television. That more or less sums up the “terrible difficulties” NBC executives face these days as they decide the fate of The Tonight Show with Conan O’Brien. Right?

Well, nobody told the so-called “younger demographic.” NBC’s clumsy approach to halting the ratings slide of its late night lineup by bumping The Tonight Show into tomorrow morning has created the biggest popular revolt of a television programming decision in recent memory. Naturally, it’s playing out on the Net.

Shortly after news leaked of the O’Brien bump, Facebook user Jonathan Harris created the “Team Conan” page in protest. “Team Conan believes that this is balderdash and that NBC should favor Conan O’Brien, unequivocally a better comic and host than Leno,” the group details in its relatively tame mission statement. Team Conan now has over 52,300 conscripts. “I’m with Coco” is even larger. It’s 81,754 members declare they will watch O’Brien at any hour on any channel. “The I’m With COCO campaign could soon become a viral sensation,” Nick O’Neil at AllFacebook.com predicts, calling it one of the fastest growing Facebook movements of the year. What’s bigger? Only the Facebook bra color campaign.

Elsewhere online, smaller protest groups have popped up to show their support for O’Brien. They include “Keep Conan O’Brien” and “Conan O’Brien > Jay Leno“; there are even groups who profess their love for his carrot-mop ‘do. There’s really no place for NBC to hide. Even the official The Tonight Show with Conan O’Brien page has been overwhelmed with supporters who do not mince words. “Keep CONAN!!!! Leno has been telling the SAME tiring lines for a decade now. NBC finally got the right man to reach the prime age demographic, and they pull him after nearly 8 months??? I’m with COCO!!!! NBC all you will have left is The Office!,” one Facebook fan agitates.

And what about the support for Leno? He’s considerably less popular. And there is a distinctly more hostile tone to how Leno is regarded by the online community. Amid the Leno groups that are gaining ground demand Leno be “fired“, “boycotted” and that he “f— off.”

The Twitterverse too is mobilizing, calling on users to “boycott Leno!”

This hostile response should hardly be surprising to NBC executives. Long before this latest programming flap, the Leno v. O’Brien rivalry has been playing out daily online. And Conan has been winning. By a massive margin. There are over 1,000 we-love-Conan Facebook fan pages and groups boasting well over 200,000 supporters. By our count, Leno has half as many supporters. That probably would surprise no-one reading this column. O’Brien is more beloved by the Facebook demographic. How NBC execs missed this obvious point is tough to fathom. This is the most coveted demographic of all, in any prime-time or late-night slot. As The Wall Street Journal reports, The Tonight Show‘s audience surged last night, “especially among younger people.” And this morning? The anti-Leno rhetoric and pro-Conan support online is surging too.