Rally organizer Mike Mitchell, the administrator of the Facebook group "I'm With COCO," acknowledged in an interview with ABCNews.com that the demonstrations likely won't change NBC's plans.
"I don't think we're going to change NBC's stance on what they want to do with late night -- I think that's already been inked," he said. "I think hopefully we're going to show Conan's got a huge following and we're behind him no matter where he ends up."
Mitchell, 27, a Los Angeles-based freelance illustrator, quickly found himself close to the O'Brien controversy after he created a black, white and orange illustration of the comedian emblazoned with the "I'm With COCO" slogan.
The Facebook group has grown from 200 members to more than 315,000 in a matter of days, he said.
"Now is just a good time to support him because he's kind of been put in a tough spot and people can relate to his situation," he said. "Everybody's had a bad boss that has maybe put them in a position that they didn't want to be in."
Mitchell said he has heard from members of O'Brien's crew who have also voiced their support for the host.
"Everybody on the show has 'I'm With CoCo' avatar on Facebook," Mitchell said, referring to his famous image. "I know personally they want to follow Conan wherever he goes … They love him and they respect him."
O'Brien's ratings, meanwhile, have surged last week as the host peppered his show with jokes at his network's expense, at one point suggesting that NBC considered him such an idiot that he might be qualified to actually run the network. His Friday ratings jumped 50 percent, and he also bested CBS' David Letterman, according to a preliminary Nielsen Co. estimate.
O'Brien's manager, Gavin Polone, told ABCNews.com that part of the reason O'Brien's ratings were lower initially was because of the weak lead-in audience provided to him by Leno's show.
On Friday, Polone said, O'Brien actually beat his predecessor, with "The Tonight Show" pulling in higher ratings than "The Jay Leno Show."
"It's pretty amazing since he's on at 11:35 and (Leno's) on at 10," Polone said.
Polone said viewers who initially who began tuning to see what O'Brien would say about the controversy ultimately decided they liked the show, helping drive the continued ratings surge.
"The ratings just kept building and building and building," he said. "If they didn't like his stuff, they wouldn't come back."
Not everyone is in O'Brien's corner.
Last week, Dick Ebersol, the chairman of NBC Universal Sports, told The New York Times that O'Brien has no one to blame for his fate besides himself and his disappointing performance and also criticized the host for mocking Leno. He said it was "chicken-hearted and gutless" of the comedian to use his shows this week "to blame a guy you couldn't beat in the ratings."
Ebersol added that "what this is really all about is an astounding failure by Conan."
With reports from The Associated Press.