Padlet is a web tool that allows you and your students to create digital bulletin boards as a space to show thinking and learning, collaborate, and communicate. It is really up to you how to use it for your community of learners. Padlet is an excellent tool because it is very versatile; it is very customizable, easy to access, has privacy protocols, and doesn't require special technology as it runs through a browser. One of its best features is that you can post files, record audio, record video, make screen capture videos, draw, add links, and add images--all from one click! It also allows you and your students to comment on anything posted.
Padlet fits very nicely with ideas around both collaboration and formative assessment. Especially the idea of setting a quick task to elicit evidence of understanding. Because Padlet requires no-student log in it is an unobtrusive activity in task that seldom breaks the learning routine.