1. A computer-implemented method, comprising: receiving, at a computing device having one or more processors, questions and answers, each question having one or more answers, and each question and each answer being associated with a particular user; receiving, at the computing device, evaluations of the answers from users; identifying, at the computing device, at least one of textual and contextual features for each answer to obtain sets of features; generating, at the computing device, a user preference graph indicating relationships between users associated with at least one of the questions, the answers, and the evaluations; and determining, at the computing device, a measure of deceptiveness for each answer based on its set of features and the user preference graph.