Zoom offers polling! In a Zoom session, the host can add polls to ask attendees questions pertaining to the presentation.
When using Google Slides, presenter can start live Q&A sessions with the audience. You can present questions at any time and people can ask questions from any device. This is a very simple tool and no need to set-up an account. It works right from within Google Slides.
Poll Everywhere has both a free basic account and more robust paid options. In the free version, users can respond to poll questions via mobile phones, Twitter, or a web browser. Responses can be seen live on a web browser or within a PowerPoint presentation. Some of the premium features with a paid account include larger audience sizes, multiple account users, team competitions, reports, grading, and technical support.
Kahoot! allows online quizzing, discussion, and surveys. Currently, you can sign up for a free account right from the home page. Once you've created your account and your first activity, users can participate using a web browser on a computer or mobile device. The account owner simply starts the activity from their account page and broadcasts it on a shared screen (Adobe Connect, classroom projector, etc) and players see a Game PIN. They navigate to https://kahoot.it/ and enter the PIN to start playing. Players can be anonymous by entering a nickname to display. For quizzes, correct answers show right away and players can see their rankings compared to classmates. Images and YouTube videos can be embedded as well.
Reef is the mobile version of iClickers. Instead of purchasing a remote students purchase the REEF Polling app. Students can then participate using their mobile devices. Students now have a choice to purchase the remote or purchase the mobile app.
i>clicker allows users to respond anonymously to questions during a class or presentation using a keypad that broadcasts to a receiver. The results can be displayed instantly, allowing instructors and presenters to obtain immediate feedback.