Simple, Simple, Simple
It is a simple way to get feedback and opinions from your class, but it needs clear guidelines to work effectively. Digital citizenship, topics and what should and should not be posted must be clear. Like so many technology solutions if anything is going to go wrong it will not be the technology, it will be the people.
How I Use It
A back channel is a great way to get more students involved in a class. I have used Todaysmeet with students and teachers alike and its simplicity is what makes it work. You do not necessarily have to have a plan to use it, it might just fit a need at the time. It has worked best when there is a clear need along with clear expectations and supervision. If any of these are not met it is easy for students (and teachers) to get off track.