Abstarct: There has been an explosive increase in the amount of misinformation prevalent in online social media.  Such content can be generated by real users or by chatbots deployed with the intention of spreading propaganda and increasing social divisiveness.  Social media platforms provide some limited mediation by flagging inappropriate content.  What is needed are scalable solutions to mitigate the spread of misinformation.  This talk focuses on the use of persuasive chatbots that can first determine the user intent and subsequently engage in conversation with online users in an attempt to slow the spread of misinformation.  We discuss the development of chatbots that incorporate theories of argumentation in conducting prolonged conversations with users.   Two case studies are presented, the first focusing on toxic speech and the second on early detection of phishing schemes.