TodaysMeet would have let teachers create private chat rooms so that students could ask questions or leave comments during class.
A Padlet wall might have fueled students to share their ideas as text, images, videos, and links posted to a digital bulletin board.
The open response questions available in a student response system like Socrative or InfuseLearning could have become discussion prompts to give each student an opportunity to share his or her ideas before engaging in class discussion.