Give all students a voice and manage burning questions
Have used this for a few years and it keeps getting better. Students can join from home or other schools or countries to expand the conversation. Teachers can really keep each room through paused rooms and access controls. You can keep rooms open all year long or for a specific period of time. It doesn't have all the pretty bells and whistles of some other apps, but it is easy to use and can really have several purposes.
How I Use It
I use it for a variety of purposes: Whole Class Discussion; Class Brainstorming Session; Group Work Sharing; Allowing students who have questions during direct instruction or work time to post questions, resources etc.