virtual exit tickets and in class assessments

Exit Ticket is a new website/app that I discovered.  It is a way for you to virtually assess your students.  You can use it as an do now/bell ringer, mid-class checks for understanding or exit tickets.  I know there are many programs out there that do similar things, but I really like ExitTicket because of all of the features that you get in the free version.  The thing that I love the most is that the free version allows you to track individual students!  Yes, the students do need to create accounts, but you can collect a lot of data.

There are so many great things that you can do with it.  They have created a toolkit for teachers to help them implement ExitTicket in their classroom.

What do you use for quick informal assessment?