Allows you to create a question and get student feedback in a visual way. You may provide multiple choice options or give students the chance to freely respond. Students may respond via text message, twitter, or computer (direct link). Helpful if you want feedback and are willing to let students use their phones. Requires you to create a free account; can be upgraded if you are willing to pay.
Allows you to create surveys with multiple question types. You can embed or directly link to the survey; it must be completed online, so students will need access to computers. Requires you to create a free account; can be upgraded if you are willing to pay. The free account will allow you to have up to 10 questions per survey and 100 responses per survey.