Promoting learner engagement in large cohorts is a well-known problem. One solution adopted in the lecture space is ‘backchannel’ software which provides an online chat facility that operates alongside the delivery of other learning activities. While this provides some protection from the collective gaze of a class backchannels often display information about a message author which may discourage them from participating. Accordingly this session will present the findings of an investigation into the impact of anonymity on backchannel engagement with a large student cohort. Subsequently despite some misuse this evaluation found that preserving anonymity is an important feature for many learners and its absence can result in a significant reduction in engagement with a backchannel.