Performance of real-time collaborative editors at large scale: User perspective

Real-time collaborative editing allows multiple users to edit a shared document at the same time. It received a lot of attention from both industry and academia and gained in popularity due to the wide availability of free services such as Google Docs. While these collaborative editing systems were initially used in scenarios involving only a small set of users such as for writing a research article, nowadays we notice a change in the scale from several users to communities of users. Group note taking during lectures or conferences is an emerging practice. An important measure of performance of real-time collaborative editing systems is delay. Delays exist between the execution of one user modification and the visibility of this modification to the other users. They can be caused by network physical communication media, complexity of consistency maintenance algorithms and system architecture. Some user studies have shown that delay affects group performance in collaborative editing. In this paper, we measure delays in popular real-time collaborative editing systems such as Google Docs and Etherpad and we study whether these systems could cope with large scale settings from a user perspective. Our results show that these systems are not yet ready for large-scale collaborative activities as either they reject new users connection or a high delay appears when facing an increasing number of users or their typing speeds in the same shared document.