App that lets teachers know students are confused in class!

Wow ----- it is amazing what some techies can come up with!  A graduate of the University of Toronto has developed a mobile application that enables students to let teachers know when they do not understand the material being presented in class.  The app explained at Understoodit.com and in the article link below, lets students click a red Confused button when they do not get the concepts presented  or the lesson or a green Understood button when they have gotten it.  An anonymous message and a graph is sent immediately to the teacher's computer.  Check out the article here at http://www.thestar.com/news/article/1173277--don-t-get-what-the-prof-s-talking-about-there-s-an-app-for-that and click on Understoodit.com to get to the web page.  Not sure there is a charge, at least check it out.  I would have loved this in Algebra class way back when.....!!!!