As online community manager at the Livestrong Foundation, Brooke McMillan has been the social-media face for an organization that has spent months at the center of an unrelenting crisis.

Last month the organization announced that its founder, Lance Armstrong, was stepping away from the group’s board and that his name would no longer be part of the organization’s official identity.  That decision came after the U.S. Anti-Doping Agency issued a detailed report about Mr. Armstrong’s use of performance-enhancement drugs and the Tour de France stripped him of medals he won.

Ms. McMillan says the constant storm of criticism of Mr. Armstrong meant she was spending time on social networks like Twitter and Facebook almost around the clock—largely working to nurture and protect an online community that still cared about the organization, despite its founder’s transgressions.

“We’re here to help people affected by cancer through daily challenges, and the way that we use social media is to connect people to services and share their stories,” she told The Chronicle. “When you build that kind of community, it’s not like you are going on Coca-Cola’s Web site and saying you like Coke Zero. You are there for a reason.”

While many supporters shared their best wishes and positive comments, some negative comments were posted on the organization’s blog and Facebook page. She says she removed some of those comments that attacked members of the community or that didn’t add anything constructive to the conversation.

In all cases, she tried to counter arguments about the organization’s founder by talking about the organization’s mission.

“Even in really, really difficult times—and I’m talking really difficult—the haters are going to be there, and they’re always going to be there and think it’s fun,” she said in a presentation at the Social Media for Nonprofits meeting in Austin. “But it is a really great way to pivot and share your mission.”

Below is a video showing Ms. McMillan’s conversation at the Austin meeting. In the comments section below, we hope you’ll share your thoughts about how charities can use social networks when a crisis or challenge erupts.