Once learned can be a effective tool for introducing concepts using visuals and interactivity.

Developed by the National Education Association covers all aspects that teachers need to know or learn in teaching an online class.

You can develop your own questions, use their test bank, or import your existing quizzes. You can select the order of the questions, indicate scores for passing, will show you their score at the completion of the quiz and reveal the correct answer to the questions. Very easy to follow. Almost no learning curve. I would definitely use this in an online class to assess students understanding of concepts covered. I would offer it either as a review or as a quiz itself.

Interesting information regarding usage of Twitter in higher education