A criminal blackmailer might threaten to use knowledge about a person's past to ruin her reputation, or ask to be paid off in cash to hide a secret. Emotional blackmail hits closer to home. Emotional blackmailers know how much we value our relationship with them. They know our vulnerabilities. Often they know our deepest secrets. And no matter how much they care about us, when they fear they won't get their way, they use this intimate knowledge to shape the threats that give them the payoff they want: our compliance.
-- Susan Forward with Donna Frazier, Emotional Blackmail, p. x