Megan Phelps-Roper was a member of the Westboro Baptist Church family, standing on picket lines holding hateful signs before she was even old enough to read them. Then they put her in charge of their Twitter account. And in the midst of all the outrage and hate, some Twitter users touched her heart and led her to leave her family's church. She has a TED talk analyzing how those users were effective:
https://www.youtube.com/watch?v=bVV2Zk88beY