My Take
I have used Poll everywhere for in class questions for the past couple of years. It is really easy to have students each answer a question using their cell phone, a computer, or a tablet. Every student gets to answer and it is a lot of fun for the students. They really enjoy seeing the immediate nature of the responses. It is a wonderful way to have a polling system in the classroom using the technology students already have versus buying an expensive student answer system.
How I Use It
I set up groups of questions that can be embedded into a powerpoint or show on a screen in the front of the room. The students then answer the questions on their own device and the answers are projected for the entire class to see. I generally use this to check understanding during a lesson or as review for a test and quiz.