Verso is a free service that offers a nice way to deliver flipped lessons to students and gather feedback from them. As a teacher you can create Verso classrooms that your students join. In your classroom you can post videos, links, and files from your Google Drive account. Include response prompts with each item that you post. You can specify how many responses you want to gather from each student.
When students sign into your Verso classroom they will see every new item you've posted for them. If you've posted a video it will play within the Verso environment. Students can track their completion progress in their account dashboards.
Verso offers free iPad and Android apps. Verso can also be used in your web browser.