81 Dash is a nice backchannel platform that I learned about today during the "Smackdown" at Hack Ed 2014. 81 Dash provides a place for teachers to create chat rooms to use with students to host conversations and share files. Once you are registered you can begin creating rooms. In your chat room you can exchange messages and files. As the owner of a room you can delete messages written by your students.
Students join your 81 Dash room by going to the URL that is assigned to your room. When they arrive at your room for the first time they will be asked to register. There are two registration options. Registering as a "guest user" does not require students to enter email addresses.
Applications for Education
81 Dash resolves the complaint that teachers have about many backchannel tools. That complaint is not having a way to delete messages or delete a room if students write inappropriate things in the backchannel.
Backchannels in general provide a good way to hear from all of the students in a classroom. A backchannel allows shy students to ask questions and share comments. For your more outspoken students who want to comment on everything, a backchannel provides a good outlet for them too.