Exploring user perceptions of deletion in mobile instant messaging applications

Contemporary mobile messaging provides rich text and multimedia functionality leaving detailed trails of sensitive user information that can span long periods of time. Allowing users to manage the privacy implications both on the sender and the receiver side can help to increase confidence in the use of communication applications. In October 2017, one of the mobile messengers with the largest user base, WhatsApp, introduced a feature to delete past messages from communication, both from the sender's and the recipient's devices. In this article, we compare the deletion features of 17 popular messaging applications. Implementations of these features widely differ across the applications we examined. We further report on a study with 125 participants conducted in a between-subjects design. We explore users' preferences for deleting mobile messages, and we investigate how well they comprehend this functionality as implemented in popular messaging applications. We found statistically significant differences in users' understanding of message deletion between our three test conditions, comprising WhatsApp, Facebook Messenger, and Skype. Eighty percent of participants in the WhatsApp condition could correctly assess the effects of deleting messages, compared to only 49% in the Skype condition. In addition, we provide insights into qualitative feedback received from our participants. Our findings indicate that message deletion is seen as a potentially useful feature that users may be able to use in different ways, including editing messages. Furthermore, users can more precisely estimate the capabilities of a deletion function when its effects are transparently explained in the application's user interface.