This paper presents a microtext corpus derived from hostage negotiation transcripts. This source was chosen for its availability and its density of persuasion: Traditional microtext sources (Twitter, SMS, chat rooms) showed "limited occurrences of directly persuasive attempts". Even the negotiation transcripts showed fewer than 12% persuasive utterances.
They definie persuasion as "the ability of one party to convince another party to act or believe in some desired way". Cialdini's persuasion model was used, focusing on:
2. Commitment and Consistency
6. Social Proof