How I Use It
In my math class I use it as a way for students to share their answer to investigation questions like "what strategies did you use to...." or "what is the relationship between...", or even just to have students share their answers. The vote on responses function works well when I want to start a discussion about why student think "that" is the correct answer.
The anonymous nature of the discussion question response can backfire however if you are not careful building your classroom expectations and culture so be aware. Luckily you can grey out response that you do not like. I also wish there were a way to pre-load discussion questions and still allow students to respond and see the live responses. The only way I've been able to load multiple questions is with the quiz function, which does not allow all responses to be shared sans names.
It's not a flashy bells and whistles type of tool but it's simplicity is part of what I like about it. Easy to set up and start using, it provides a great way to let all students have a voice in a classroom discussion. No more, "he stole my idea" or "oh I forgot what I was going to say". In real time, you can see what your students are thinking, and so can they!. The fact that the posts can be anonymous means students can take risks that they might not take if they had to raise their hand. And the teacher doesn't have to wait for kids to turn in papers to gauge how well things are going.