Padlet, formerly Wallwisher, is a site to do collaborative work. If you never tried Wallwisher or paadlet, don't let fear of something new stop you, because it is very simple to use. To get started simply go to padlet.com and click "build a wall." Next, title your wall, choose a URL for your wall, enter your name and email, and start adding sticky notes to the wall. Not only can you put up to 160 characters in a stickynote, but you can put in images, youtube videos, and other documents on to your padlet wall. It is up to you whether your wall is public or private. You can control the settings so that if you want to approve additions to the wall before they appear, that's a posibility too. You may want to choose the public settings when using this in a classroom setting so you only need to give students the URL of your wall in order for them to add notes to it.