Clickers are electronic response devices with which a student can remotely submit responses to questions or problems posed by a teacher. The problems are typically true-false or multiple-choice questions, but can also include numerical problems. Clicker devices are particularly popular in large-enrollment introductory science, technology, engineering, and mathematics courses. A taxonomy of clicker use is introduced to classify the wide variety of tasks that may be accomplished with clickers. The taxonomy distinguishes between two key categories. The first category relates to questions probing attendance in class, preparedness of assigned reading, and interest in the subject matter. The second category pertains to activities for the enhancement of conceptual understanding and mastering of the material. It involves connecting clicker use to teaching and learning strategies that are thought-provoking, such as peer instruction and problem-based learning. Categories and subcategories are illustrated with key examples of clicker questions from a nonmajor introductory general chemistry course at the college or university level. (Contains 2 figures and 3 notes.)