When faced with a crisis, many nonprofits stay silent until they are sure they have created the right message to share with their supporters.

Amy Bryant, digital content manager at the Planned Parenthood Federation of America, says that can be a big mistake. Groups that are facing a public crisis or challenge need to take control of the message early—even if they are still trying to react to that crisis, she told a session at the South by Southwest Interactive conference, in Austin, Tex. That is especially true in social networks.

“Even if you put up a statement that says ‘Yes, we know it’s happening. Give us some time to figure it out,’ that’s enough,” says her colleague, Stephanie Lauf, Planned Parenthood’s director of online-supporter engagement, who also spoke at the conference. That practice has been especially important for Planned Parenthood over the past year, as it has found itself at the center of two high-profile controversies.

In 2011, Congress proposed legislation that would eliminate the federal government’s $317-million family-planning program and bar any federal funds for Planned Parenthood. In January, Susan G. Komen for the Cure said it would pull financial support from the organization.

In both cases, Planned Parenthood used highly coordinated social-media campaigns to rally its supporters. And in both cases, the organization was able to preserve its support.

The group won these victories in part because of its ability to use social networks like Twitter, Facebook, and YouTube to communicate with supporters and offer them opportunities to fight the proposals.

During the battle over federal  aid, the organization gave supporters daily updates on what was happening in  Washington, provided easy ways for them to contact lawmakers, and created a dedicated page on  its Web site to provide information and background on the issue.

It took a similar approach during the Komen controversy—posting messages on Facebook and sending e-mails to supporters almost immediately after news broke of the breast-cancer charity’s decision. Those e-mail messages, sent with the subject line “Disappointing News From a Friend,” included an appeal to supporters to help make up for the money that would be lost as a result of Komen’s decision.

Subsequent messages sought to rally public support.

“When you have funding pulled, the reaction is to fill back up that pot,” says Ms. Lauf. “But we recognized that we also needed to have something else for them to do beyond making a gift.”